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  6.     <title>Chapter¬†6.¬† Getting images out of GIMP</title>
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  13.     <link rel="up" href="pt02.html" title="Part¬†II.¬† How do I Become a GIMP Wizard?" />
  14.     <link rel="prev" href="ch05s03s07.html" title="3.7.¬† Image Browser" />
  15.     <link rel="next" href="gimp-using-web.html" title="2.¬† Preparing your Images for the Web" />
  16.   </head>
  17.   <body>
  18.     <div class="navheader">
  19.       <table width="100%" summary="Navigation header">
  20.         <tr>
  21.           <th colspan="3" align="center">Chapter¬†6.¬†
  22.         <span lang="en" xml:lang="en">Getting images out of GIMP</span>
  23.       </th>
  24.         </tr>
  25.         <tr>
  26.           <td width="20%" align="left"><a accesskey="p" href="ch05s03s07.html"><img src="../images/prev.png" alt="Prev" /></a>¬†</td>
  27.           <th width="60%" align="center">Part¬†II.¬†
  28.       <span lang="en" xml:lang="en">
  29.         How do I Become a <acronym class="acronym">GIMP</acronym> Wizard?
  30.       </span>
  31.     </th>
  32.           <td width="20%" align="right">¬†<a accesskey="n" href="gimp-using-web.html"><img src="../images/next.png" alt="Next" /></a></td>
  33.         </tr>
  34.       </table>
  35.       <hr />
  36.     </div>
  37.     <div class="chapter" lang="en" xml:lang="en">
  38.       <div class="titlepage">
  39.         <div>
  40.           <div>
  41.             <h2 class="title"><a id="gimp-images-out"></a>Chapter¬†6.¬†
  42.         <span lang="en" xml:lang="en">Getting images out of GIMP</span>
  43.       </h2>
  44.           </div>
  45.         </div>
  46.       </div>
  47.       <div class="toc">
  48.         <p>
  49.           <b>Table of Contents</b>
  50.         </p>
  51.         <dl>
  52.           <dt>
  53.             <span class="sect1">
  54.               <a href="gimp-images-out.html#gimp-using-fileformats">1. 
  55.     <span lang="en" xml:lang="en">Files</span>
  56.   </a>
  57.             </span>
  58.           </dt>
  59.           <dd>
  60.             <dl>
  61.               <dt>
  62.                 <span class="sect2">
  63.                   <a href="gimp-images-out.html#id2589134">1.1. 
  64.       <span lang="en" xml:lang="en">Saving Images</span>
  65.     </a>
  66.                 </span>
  67.               </dt>
  68.               <dt>
  69.                 <span class="sect2">
  70.                   <a href="gimp-images-out.html#gimp-using-fileformats-export-dialog">1.2. 
  71.       <span lang="en" xml:lang="en">Saving Files</span>
  72.     </a>
  73.                 </span>
  74.               </dt>
  75.             </dl>
  76.           </dd>
  77.           <dt>
  78.             <span class="sect1">
  79.               <a href="gimp-using-web.html">2. 
  80.     <span lang="en" xml:lang="en">Preparing your Images for the Web</span>
  81.   </a>
  82.             </span>
  83.           </dt>
  84.           <dd>
  85.             <dl>
  86.               <dt>
  87.                 <span class="sect2">
  88.                   <a href="gimp-using-web.html#gimp-using-web-size-vs-quality">2.1. 
  89.       <span lang="en" xml:lang="en">Images with an Optimal Size/Quality Ratio</span>
  90.     </a>
  91.                 </span>
  92.               </dt>
  93.               <dt>
  94.                 <span class="sect2">
  95.                   <a href="gimp-using-web-reducing-file-size.html">2.2. 
  96.       <span lang="en" xml:lang="en">Reducing the File Size Even More</span>
  97.     </a>
  98.                 </span>
  99.               </dt>
  100.               <dt>
  101.                 <span class="sect2">
  102.                   <a href="gimp-using-web-transparency.html">2.3. 
  103.       <span lang="en" xml:lang="en">Saving Images with Transparency</span>
  104.     </a>
  105.                 </span>
  106.               </dt>
  107.             </dl>
  108.           </dd>
  109.         </dl>
  110.       </div>
  111.       <div class="sect1" lang="en" xml:lang="en">
  112.         <div class="titlepage">
  113.           <div>
  114.             <div>
  115.               <h2 class="title" style="clear: both"><a id="gimp-using-fileformats"></a>1.¬†
  116.     <span lang="en" xml:lang="en">Files</span>
  117.   </h2>
  118.             </div>
  119.             <div>
  120.               <div class="revhistory">
  121.                 <table border="1" width="100%" summary="Revision history">
  122.                   <tr>
  123.                     <th align="left" valign="top" colspan="3">
  124.                       <b>Revision History</b>
  125.                     </th>
  126.                   </tr>
  127.                   <tr>
  128.                     <td align="left">Revision $Revision: 2416 $</td>
  129.                     <td align="left">2007-10-06</td>
  130.                     <td align="left">ude</td>
  131.                   </tr>
  132.                 </table>
  133.               </div>
  134.             </div>
  135.           </div>
  136.         </div>
  137.         <a id="id2589098" class="indexterm"></a>
  138.         <p>
  139.     The <acronym class="acronym">GIMP</acronym> is capable of reading and writing a large
  140.     variety of graphics file formats.  With the exception of
  141.     <acronym class="acronym">GIMP</acronym>'s native XCF file type, file handling is done by
  142.     Plugins.  Thus, it is relatively easy to extend <acronym class="acronym">GIMP</acronym>
  143.     to new file types when the need arises.
  144.   </p>
  145.         <p>
  146.     Not all file types are equally good for all purposes. This part of the
  147.     documentation should help you understand the advantages and disadvantages
  148.     of each type.
  149.   </p>
  150.         <div class="sect2" lang="en" xml:lang="en">
  151.           <div class="titlepage">
  152.             <div>
  153.               <div>
  154.                 <h3 class="title"><a id="id2589134"></a>1.1.¬†
  155.       <span lang="en" xml:lang="en">Saving Images</span>
  156.     </h3>
  157.               </div>
  158.             </div>
  159.           </div>
  160.           <p>
  161.       When you are finished working with an image, you will want to save the
  162.       results. (In fact, it is often a good idea to save at intermediate
  163.       stages too: <acronym class="acronym">GIMP</acronym>
  164.       is a pretty robust program, but we have heard rumors, possibly
  165.       apocryphal, that it may have been known on rare and mysterious occasions
  166.       to crash.) Most of the file formats that <acronym class="acronym">GIMP</acronym>
  167.       can open, can also be used for saving. There is one file format that is
  168.       special, though: XCF is <acronym class="acronym">GIMP</acronym>'s native format, and is
  169.       useful because it stores <span class="emphasis"><em>everything</em></span> about an image
  170.       (well, almost everything; it does not store ‚Äú<span class="quote">undo</span>‚Äù
  171.       information). Thus, the XCF format is especially suitable for saving
  172.       intermediate results, and for saving images to be re-opened later in
  173.       <acronym class="acronym">GIMP</acronym>.
  174.       XCF files are not readable by most other programs that display images,
  175.       so once you have finished, you will probably also want to save the image
  176.       in a more widely used format, such as JPEG, PNG, TIFF, etc.
  177.     </p>
  178.         </div>
  179.         <div class="sect2" lang="en" xml:lang="en">
  180.           <div class="titlepage">
  181.             <div>
  182.               <div>
  183.                 <h3 class="title"><a id="gimp-using-fileformats-export-dialog"></a>1.2.¬†
  184.       <span lang="en" xml:lang="en">Saving Files</span>
  185.     </h3>
  186.               </div>
  187.             </div>
  188.           </div>
  189.           <p>
  190.       There are several commands for saving images. A list, and information on
  191.       how to use them, can be found in the section covering the
  192.       <a class="link" href="gimp-image-window-menus-file.html" title="5.¬† The ‚ÄúFile‚Äù Menu">File Menu</a>.
  193.     </p>
  194.           <p>
  195.       <acronym class="acronym">GIMP</acronym> allows you to save the images you create in a
  196.       wide variety of formats.  It is important to realize that the only
  197.       format capable of saving <span class="emphasis"><em>all</em></span> of the information in
  198.       an image, including layers, transparency, etc., is GIMP's native XCF
  199.       format.   Every other format preserves some image properties and loses
  200.       others.  When you save an image, <acronym class="acronym">GIMP</acronym> tries to let
  201.       you know about this, but basically it is up to you to understand the
  202.       capabilities of the format you choose.
  203.     </p>
  204.           <div class="figure">
  205.             <a id="id2589241"></a>
  206.             <p class="title">
  207.               <b>Figure¬†6.1.¬†
  208.         <span lang="en" xml:lang="en">Example of an Export dialog</span>
  209.       </b>
  210.             </p>
  211.             <div class="figure-contents">
  212.               <div class="mediaobject">
  213.                 <img src="../images/using/export-dialog.png" alt="Example of an Export dialog" />
  214.               </div>
  215.             </div>
  216.           </div>
  217.           <br class="figure-break" />
  218.           <p>
  219.       As stated above, there is no file format, with the exception of GIMP's
  220.       native <a class="link" href="glossary.html#glossary-xcf" title="XCF">XCF</a> format, that is capable
  221.       of storing all the data in a <acronym class="acronym">GIMP</acronym>
  222.       image. When you ask to save an image in a format that will not
  223.       completely represent it, <acronym class="acronym">GIMP</acronym>
  224.       notifies you of this, tells you what kind of information will be lost,
  225.       and asks you whether you would like to ‚Äú<span class="quote">export</span>‚Äù the image
  226.       in a form that the file type can handle. Exporting an image does not
  227.       modify the image itself, so you do not lose anything by doing this. See
  228.       <a class="link" href="gimp-export-dialog.html" title="5.4.¬† Export File">Export file</a>.
  229.     </p>
  230.           <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
  231.             <table border="0" summary="Note">
  232.               <tr>
  233.                 <td rowspan="2" align="center" valign="top" width="25">
  234.                   <img alt="[Note]" src="../images/note.png" />
  235.                 </td>
  236.                 <th align="left">Note</th>
  237.               </tr>
  238.               <tr>
  239.                 <td align="left" valign="top">
  240.                   <p>
  241.         When you close an image (possibly by quitting GIMP), you are warned if
  242.         the image is "dirty"; that is, if it has been changed without
  243.         subsequently being saved. Saving an image in any file format will
  244.         cause the image to be considered "not dirty", even if the file format
  245.         does not represent all of the information from the image.
  246.       </p>
  247.                 </td>
  248.               </tr>
  249.             </table>
  250.           </div>
  251.           <div class="sect3" lang="en" xml:lang="en">
  252.             <div class="titlepage">
  253.               <div>
  254.                 <div>
  255.                   <h4 class="title"><a id="file-gif-save"></a>1.2.1.¬†
  256.         <span lang="en" xml:lang="en">Saving as GIF</span>
  257.       </h4>
  258.                 </div>
  259.               </div>
  260.             </div>
  261.             <a id="file-gif-load"></a>
  262.             <a id="id2589341" class="indexterm"></a>
  263.             <a id="id2589348" class="indexterm"></a>
  264.             <a id="id2589354" class="indexterm"></a>
  265.             <a id="id2589362" class="indexterm"></a>
  266.             <div class="figure">
  267.               <a id="id2589375"></a>
  268.               <p class="title">
  269.                 <b>Figure¬†6.2.¬†
  270.           <span lang="en" xml:lang="en">The GIF Save dialog</span>
  271.         </b>
  272.               </p>
  273.               <div class="figure-contents">
  274.                 <div class="mediaobject">
  275.                   <img src="../images/using/gif-save-dialog.png" alt="The GIF Save dialog" />
  276.                 </div>
  277.               </div>
  278.             </div>
  279.             <br class="figure-break" />
  280.             <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
  281.               <table border="0" summary="Warning">
  282.                 <tr>
  283.                   <td rowspan="2" align="center" valign="top" width="25">
  284.                     <img alt="[Warning]" src="../images/warning.png" />
  285.                   </td>
  286.                   <th align="left">Warning</th>
  287.                 </tr>
  288.                 <tr>
  289.                   <td align="left" valign="top">
  290.                     <p>
  291.           Please note, that the GIF file format is incapable of storing some
  292.           rather basic image informations like
  293.           <span class="emphasis"><em>print resolution</em></span>.
  294.           If you care for these properties, you should consider a different
  295.           file format like PNG.
  296.         </p>
  297.                   </td>
  298.                 </tr>
  299.               </table>
  300.             </div>
  301.             <div class="variablelist">
  302.               <dl>
  303.                 <dt>
  304.                   <span class="term">GIF Options</span>
  305.                 </dt>
  306.                 <dd>
  307.                   <div class="variablelist">
  308.                     <dl>
  309.                       <dt>
  310.                         <span class="term">Interlace</span>
  311.                       </dt>
  312.                       <dd>
  313.                         <p>
  314.                     <span class="guilabel">Interlace</span>
  315.                     : when this option is checked, the image will be displayed
  316.                     progressively on the Web page. It was interesting when
  317.                     computers and modems were slow, as it allowed to stop
  318.                     loading an image of no interest.
  319.                   </p>
  320.                       </dd>
  321.                       <dt>
  322.                         <span class="term">GIF comment</span>
  323.                       </dt>
  324.                       <dd>
  325.                         <p>
  326.                     Beware of do not insert characters outside the ASCII
  327.                     range, because of the GIF format supports 7-bits ASCII
  328.                     texts only, that GIMP can't provide. If you insert
  329.                     inadvertently a non-ASCII char, the option will be
  330.                     automatically disabled.
  331.                   </p>
  332.                       </dd>
  333.                     </dl>
  334.                   </div>
  335.                 </dd>
  336.                 <dt>
  337.                   <span class="term">Animated GIF Options</span>
  338.                 </dt>
  339.                 <dd>
  340.                   <a id="id2589500" class="indexterm"></a>
  341.                   <div class="variablelist">
  342.                     <dl>
  343.                       <dt>
  344.                         <span class="term">Loop forever</span>
  345.                       </dt>
  346.                       <dd>
  347.                         <p>
  348.                     <span class="guilabel">Loop forever</span>
  349.                     : when this option is checked the animation will start
  350.                     playing again repeatedly until you stop it.
  351.                   </p>
  352.                       </dd>
  353.                       <dt>
  354.                         <span class="term">Delay between frames if unspecified</span>
  355.                       </dt>
  356.                       <dd>
  357.                         <p>
  358.                     <span class="guilabel">Delay between frames if unspecified</span>
  359.                     : you can set the delay, in millisecondes, between frames
  360.                     if it has not been set before. In this case, you can
  361.                     modify every delay in the Layer Dialog.
  362.                   </p>
  363.                       </dd>
  364.                       <dt>
  365.                         <span class="term">Frame disposal when unspecified</span>
  366.                       </dt>
  367.                       <dd>
  368.                         <p>
  369.                     <span class="guilabel">Frame disposal when unspecified</span>
  370.                     : If this has not been set before, you can set how frames
  371.                     will be superimposed. You can select among three options :
  372.                   </p>
  373.                         <div class="itemizedlist">
  374.                           <ul type="opencircle">
  375.                             <li style="list-style-type: circle">
  376.                               <p>
  377.                         <span class="guilabel">I don't care</span>
  378.                         : you can use this option if all your layers are
  379.                         opaque. Layers will overwrite what is beneath.
  380.                       </p>
  381.                             </li>
  382.                             <li style="list-style-type: circle">
  383.                               <p>
  384.                         <span class="guilabel">Cumulative Layers (combine)</span>
  385.                         : previous frames will not be deleted when a new one
  386.                         is displayed.
  387.                       </p>
  388.                             </li>
  389.                             <li style="list-style-type: circle">
  390.                               <p>
  391.                         <span class="guilabel">One frame per layer (replace)</span>
  392.                         : previous frames will be deleted before displaying a
  393.                         new frame.
  394.                       </p>
  395.                             </li>
  396.                           </ul>
  397.                         </div>
  398.                       </dd>
  399.                     </dl>
  400.                   </div>
  401.                 </dd>
  402.               </dl>
  403.             </div>
  404.           </div>
  405.           <div class="sect3" lang="en" xml:lang="en">
  406.             <div class="titlepage">
  407.               <div>
  408.                 <div>
  409.                   <h4 class="title"><a id="file-jpeg-save"></a>1.2.2.¬†
  410.         <span lang="en" xml:lang="en">Saving as JPEG</span>
  411.       </h4>
  412.                 </div>
  413.               </div>
  414.             </div>
  415.             <a id="file-jpeg-load"></a>
  416.             <a id="id2589675" class="indexterm"></a>
  417.             <a id="id2589681" class="indexterm"></a>
  418.             <a id="id2589687" class="indexterm"></a>
  419.             <a id="id2589693" class="indexterm"></a>
  420.             <a id="id2589702" class="indexterm"></a>
  421.             <p>
  422.         JPEG files usually have an extension .jpg, .JPG, or .jpeg. It is a
  423.         very widely used format, because it compresses images very
  424.         efficiently, while minimizing the loss of image quality. No other
  425.         format comes close to achieving the same level of compression. It does
  426.         not, however, support transparency or multiple layers. For this
  427.         reason, saving images as JPEG often requires them to be exported from
  428.         <acronym class="acronym">GIMP</acronym>.
  429.       </p>
  430.             <div class="figure">
  431.               <a id="id2589730"></a>
  432.               <p class="title">
  433.                 <b>Figure¬†6.3.¬†
  434.           <span lang="en" xml:lang="en">The JPEG Save dialog</span>
  435.         </b>
  436.               </p>
  437.               <div class="figure-contents">
  438.                 <div class="mediaobject">
  439.                   <img src="../images/using/save-jpeg-dialog.png" alt="The JPEG Save dialog" />
  440.                 </div>
  441.               </div>
  442.             </div>
  443.             <br class="figure-break" />
  444.             <p>
  445.         The JPEG algorithm is quite complex, and involves a bewildering number
  446.         of options, whose meaning is beyond the scope of this documentation.
  447.         Unless you are a JPEG expert, the Quality parameter is probably the
  448.         only one you will need to adjust.
  449.       </p>
  450.             <p>
  451.         </p>
  452.             <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
  453.               <table border="0" summary="Caution">
  454.                 <tr>
  455.                   <td rowspan="2" align="center" valign="top" width="25">
  456.                     <img alt="[Caution]" src="../images/caution.png" />
  457.                   </td>
  458.                   <th align="left">Caution</th>
  459.                 </tr>
  460.                 <tr>
  461.                   <td align="left" valign="top">
  462.                     <p>
  463.             After you save an image as a JPEG file, the image is no longer
  464.             considered ‚Äú<span class="quote">dirty</span>‚Äù by <acronym class="acronym">GIMP</acronym>,
  465.             so unless you make further changes to it, you will not receive
  466.             any warning if you close it. Because JPEG is lossy and does not
  467.             support transparency or multiple layers, some of the information
  468.             in the image might then be lost. If you want to save all of the
  469.             information in an image, use <acronym class="acronym">GIMP</acronym>'s native
  470.             <a class="link" href="glossary.html#glossary-xcf" title="XCF">XCF format</a>.
  471.           </p>
  472.                   </td>
  473.                 </tr>
  474.               </table>
  475.             </div>
  476.             <p>
  477.       </p>
  478.             <div class="variablelist">
  479.               <dl>
  480.                 <dt>
  481.                   <span class="term">Quality</span>
  482.                 </dt>
  483.                 <dd>
  484.                   <p>
  485.               When you save a file in JPEG format, a dialog is displayed
  486.               that allows you to set the Quality level, which ranges from 0
  487.               to 100. Values above 95 are generally not useful, though. The
  488.               default quality of 85 usually produces excellent results, but
  489.               in many cases it is possible to set the quality substantially
  490.               lower without noticeably degrading the image. You can test the
  491.               effect of different quality settings by checking
  492.               <span class="guilabel">Show Preview in image window</span>
  493.               in the JPEG dialog.
  494.             </p>
  495.                   <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
  496.                     <table border="0" summary="Note">
  497.                       <tr>
  498.                         <td rowspan="2" align="center" valign="top" width="25">
  499.                           <img alt="[Note]" src="../images/note.png" />
  500.                         </td>
  501.                         <th align="left">Note</th>
  502.                       </tr>
  503.                       <tr>
  504.                         <td align="left" valign="top">
  505.                           <p>
  506.                 Please note, that the numbers for the JPEG quality level have
  507.                 a different meaning. Saving with a level of 80 in GIMP is not
  508.                 necessarily comparable with saving with a level of 80 in an
  509.                 different application.
  510.               </p>
  511.                         </td>
  512.                       </tr>
  513.                     </table>
  514.                   </div>
  515.                 </dd>
  516.                 <dt>
  517.                   <span class="term">Preview in image window</span>
  518.                 </dt>
  519.                 <dd>
  520.                   <p>
  521.               Checking this option causes each change in quality (or any other
  522.               JPEG parameter) to be shown in the image display. (This does not
  523.               alter the image, though: it reverts back to its original state
  524.               when the JPEG dialog is closed.)
  525.             </p>
  526.                 </dd>
  527.                 <dt>
  528.                   <span class="term">Advanced settings</span>
  529.                 </dt>
  530.                 <dd>
  531.                   <p>
  532.               Some information about the advanced settings:
  533.             </p>
  534.                   <div class="variablelist">
  535.                     <dl>
  536.                       <dt>
  537.                         <span class="term">Optimize</span>
  538.                       </dt>
  539.                       <dd>
  540.                         <p>
  541.                     If you enable this option, the optimization of entropy
  542.                     encoding parameters will be used.
  543.                   </p>
  544.                       </dd>
  545.                       <dt>
  546.                         <span class="term">Progressive</span>
  547.                       </dt>
  548.                       <dd>
  549.                         <p>
  550.                     With this option enabled the chunks of the image will be
  551.                     inserted in a certain order in the file. This is done with
  552.                     the intent to give a progressive refinement of the image
  553.                     appearance during a slow connection web download, similar
  554.                     and with the same purpose of the corresponding option
  555.                     present in the GIF format too. The downside of enabling
  556.                     this option is, that you get slightly larger files.
  557.                   </p>
  558.                       </dd>
  559.                       <dt>
  560.                         <span class="term">Save EXIF data</span>
  561.                       </dt>
  562.                       <dd>
  563.                         <a id="id2589966" class="indexterm"></a>
  564.                         <p>
  565.                     JPEG files from many digital cameras contain extra
  566.                     information, called EXIF data, which specifies camera
  567.                     settings and other information concerning the
  568.                     circumstances under which the image was created. GIMP's
  569.                     ability to handle EXIF data depends on whether the
  570.                     ‚Äú<span class="quote">libexif</span>‚Äù
  571.                     library is available on your system; it is not
  572.                     automatically packaged with GIMP. If GIMP was built with
  573.                     libexif support, then EXIF data is preserved if you open a
  574.                     JPEG file, work with the resulting image, and then save it
  575.                     as JPEG. The EXIF data is not altered in any way when you
  576.                     do this (which means that some of its fields are no longer
  577.                     valid). If GIMP was not built with EXIF support, this does
  578.                     not prevent files with EXIF data from being opened, but it
  579.                     does mean that the EXIF data will not be present when the
  580.                     resulting image is later saved.
  581.                   </p>
  582.                       </dd>
  583.                       <dt>
  584.                         <span class="term">Save Preview</span>
  585.                       </dt>
  586.                       <dd>
  587.                         <p>
  588.                     This option lets you save a thumbnail with the image.
  589.                   </p>
  590.                       </dd>
  591.                       <dt>
  592.                         <span class="term">Save XMP data</span>
  593.                       </dt>
  594.                       <dd>
  595.                         <p>
  596.                     If you enable this option, the meta data of the image will
  597.                     be saved as <acronym class="acronym">XMP</acronym>-structure within the
  598.                     file.
  599.                   </p>
  600.                       </dd>
  601.                       <dt>
  602.                         <span class="term">
  603.                   Use quality settings from original image
  604.                 </span>
  605.                       </dt>
  606.                       <dd>
  607.                         <p>
  608.                     If a particular quality setting (or
  609.                     ‚Äú<span class="quote">quantization table</span>‚Äù
  610.                     ) was attached to the image when it was loaded, then this
  611.                     option allows you to use them instead of the standard
  612.                     ones.
  613.                   </p>
  614.                         <p>
  615.                     If you have only made a few changes to the image, then
  616.                     re-using the same quality setting will give you almost the
  617.                     same quality and file size as the original image. This
  618.                     will minimize the losses caused by the quantization step,
  619.                     compared to what would happen if you used different
  620.                     quality setting.
  621.                   </p>
  622.                         <p>
  623.                     If the quality setting found in the original file are not
  624.                     better than your default quality settings, then the option
  625.                     ‚Äú<span class="quote">Use quality settings from original image</span>‚Äù
  626.                     will be available but not enabled. This ensures that you
  627.                     always get at least the minimum quality specified in your
  628.                     defaults. If you did not make major changes to the image
  629.                     and you want to save it using the same quality as the
  630.                     original, then you can do it by enabling this option.
  631.                   </p>
  632.                       </dd>
  633.                       <dt>
  634.                         <span class="term">Smoothing</span>
  635.                       </dt>
  636.                       <dd>
  637.                         <p>
  638.                     Compression can create artefacts. By using this option,
  639.                     you can smooth the image when saving, reducing them. But
  640.                     your image becomes somewhat blurred.
  641.                   </p>
  642.                       </dd>
  643.                       <dt>
  644.                         <span class="term">Restart markers</span>
  645.                       </dt>
  646.                       <dd>
  647.                         <p>
  648.                     The image file can include some markers which allow to
  649.                     segment it. If loading this image in a Web page is broken
  650.                     off, loading can resume from the following marker.
  651.                   </p>
  652.                       </dd>
  653.                       <dt>
  654.                         <span class="term">Subsampling</span>
  655.                       </dt>
  656.                       <dd>
  657.                         <p>
  658.                     Human eye is not sensitive in the same way all over color
  659.                     spectrum. Compression can use this to consider as
  660.                     identical slightly different colors. Three methods are
  661.                     available :
  662.                   </p>
  663.                         <div class="itemizedlist">
  664.                           <ul type="disc">
  665.                             <li>
  666.                               <p>
  667.                         <span class="guilabel">1x1,1x1,1x1 (best quality)</span>
  668.                         : preserves borders and contrasting colors, but
  669.                         compression is less.
  670.                       </p>
  671.                             </li>
  672.                             <li>
  673.                               <p>
  674.                         <span class="guilabel">2x1,1x1,1x1 (4:2:2)</span>
  675.                       </p>
  676.                             </li>
  677.                             <li>
  678.                               <p>
  679.                         <span class="guilabel">1x2,1x1,1x1</span>
  680.                       </p>
  681.                             </li>
  682.                             <li>
  683.                               <p>
  684.                         <span class="guilabel">2x2,1x1,1x1 (smallest file)</span>
  685.                         : important compression; suits images with weak
  686.                         borders but tends to denature colors.
  687.                       </p>
  688.                             </li>
  689.                           </ul>
  690.                         </div>
  691.                       </dd>
  692.                       <dt>
  693.                         <span class="term">DCT Method</span>
  694.                       </dt>
  695.                       <dd>
  696.                         <p>
  697.                     DCT is ‚Äú<span class="quote">discrete cosine transform</span>‚Äù,
  698.                     and it is the first step in the JPEG algorithm going
  699.                     from the spatial to the frequency domain. The choices are
  700.                     ‚Äú<span class="quote">float</span>‚Äù, ‚Äú<span class="quote">integer</span>‚Äù
  701.                     (the default), and ‚Äú<span class="quote">fast integer</span>‚Äù.
  702.                   </p>
  703.                         <div class="itemizedlist">
  704.                           <ul type="disc">
  705.                             <li>
  706.                               <p>
  707.                         <span class="guilabel">float</span>
  708.                         : The float method is very slightly more accurate than
  709.                         the integer method, but is much slower unless your
  710.                         machine has very fast floating-point hardware. Also
  711.                         note that the results of the floating-point method may
  712.                         vary slightly across machines, while the integer
  713.                         methods should give the same results everywhere.
  714.                       </p>
  715.                             </li>
  716.                             <li>
  717.                               <p>
  718.                         <span class="guilabel">integer</span>
  719.                         (the default): This method is faster than
  720.                         ‚Äú<span class="quote">float</span>‚Äù, but not as accurate.
  721.                       </p>
  722.                             </li>
  723.                             <li>
  724.                               <p>
  725.                         <span class="guilabel">fast integer</span>
  726.                         : The fast integer method is much less accurate than
  727.                         the other two.
  728.                       </p>
  729.                             </li>
  730.                           </ul>
  731.                         </div>
  732.                       </dd>
  733.                       <dt>
  734.                         <span class="term">Image comments</span>
  735.                       </dt>
  736.                       <dd>
  737.                         <p>
  738.                     In this text box, you can enter a comment which will be
  739.                     saved with the image.
  740.                   </p>
  741.                       </dd>
  742.                     </dl>
  743.                   </div>
  744.                 </dd>
  745.               </dl>
  746.             </div>
  747.           </div>
  748.           <div class="sect3" lang="en" xml:lang="en">
  749.             <div class="titlepage">
  750.               <div>
  751.                 <div>
  752.                   <h4 class="title"><a id="file-png-save"></a>1.2.3.¬†
  753.         <span lang="en" xml:lang="en">Saving as PNG</span>
  754.       </h4>
  755.                 </div>
  756.               </div>
  757.             </div>
  758.             <a id="file-png-load"></a>
  759.             <a id="file-png-save-defaults"></a>
  760.             <a id="id2590405" class="indexterm"></a>
  761.             <a id="id2590413" class="indexterm"></a>
  762.             <a id="id2590422" class="indexterm"></a>
  763.             <div class="figure">
  764.               <a id="id2590435"></a>
  765.               <p class="title">
  766.                 <b>Figure¬†6.4.¬†
  767.           <span lang="en" xml:lang="en">
  768.             The ‚Äú<span class="quote">Save as PNG</span>‚Äù dialog
  769.           </span>
  770.         </b>
  771.               </p>
  772.               <div class="figure-contents">
  773.                 <div class="mediaobject">
  774.                   <img src="../images/using/save-png-dialog.png" alt="The Save as PNG dialog" />
  775.                 </div>
  776.               </div>
  777.             </div>
  778.             <br class="figure-break" />
  779.             <div class="variablelist">
  780.               <dl>
  781.                 <dt>
  782.                   <span class="term">Interlacing</span>
  783.                 </dt>
  784.                 <dd>
  785.                   <p>
  786.               <span class="guilabel">Interlacing</span>: When this option is checked,
  787.               the image is progressively displayed on a Web page. So, slow
  788.               computer users can stop downloading if they are not interested.
  789.             </p>
  790.                 </dd>
  791.                 <dt>
  792.                   <span class="term">Save background color</span>
  793.                 </dt>
  794.                 <dd>
  795.                   <p>
  796.               <span class="guilabel">Save background color</span>
  797.               : If your image has many transparency levels, the Internet
  798.               browsers which recognize only two levels, will use the
  799.               background color of your Toolbox instead. But Internet Explorer
  800.               up to version 6 does not use these informations.
  801.             </p>
  802.                 </dd>
  803.                 <dt>
  804.                   <span class="term">Save gamma</span>
  805.                 </dt>
  806.                 <dd>
  807.                   <p>
  808.               <span class="guilabel">Save gamma</span>: informations about your
  809.               monitor will be saved, so that the image will be displayed in
  810.               the same way on other computers, provided that the display
  811.               program supports these informations, what is rarely the case.
  812.             </p>
  813.                 </dd>
  814.                 <dt>
  815.                   <span class="term">Save layer offset</span>
  816.                 </dt>
  817.                 <dd>
  818.                   <p>
  819.               <span class="guilabel">Save layer offset</span>: No interest. Images
  820.               with layers are flattened before saving to PNG and layer
  821.               offset is taken in account.
  822.             </p>
  823.                 </dd>
  824.                 <dt>
  825.                   <span class="term">Save Resolution</span>
  826.                 </dt>
  827.                 <dd>
  828.                   <p>
  829.               <span class="guilabel">Save Resolution</span>: Save the image
  830.               resolution, in dpi (dot per inch).
  831.             </p>
  832.                 </dd>
  833.                 <dt>
  834.                   <span class="term">Save creation time</span>
  835.                 </dt>
  836.                 <dd>
  837.                   <p>
  838.               <span class="guilabel">Save creation time</span>: That will be the date
  839.               of last saving.
  840.             </p>
  841.                 </dd>
  842.                 <dt>
  843.                   <span class="term">Save comment</span>
  844.                 </dt>
  845.                 <dd>
  846.                   <p>
  847.               <span class="guilabel">Save comment</span>: you can read this comment
  848.               in the <a class="link" href="gimp-image-properties.html" title="9.27.¬† Image Properties">Image
  849.               Properties</a>.
  850.             </p>
  851.                 </dd>
  852.                 <dt>
  853.                   <span class="term">Save color values from transparent pixels</span>
  854.                 </dt>
  855.                 <dd>
  856.                   <p>
  857.               With this option is checked, the color values are saved even if the
  858.               pixels are completely transparent.
  859.             </p>
  860.                 </dd>
  861.                 <dt>
  862.                   <span class="term">Compression level</span>
  863.                 </dt>
  864.                 <dd>
  865.                   <p>
  866.               <span class="guilabel">Compression level</span>: Since compression is
  867.               not lossy, the only reason to use a compression level less
  868.               than 9 would be a too long time to compress file on a slow
  869.               computer. Nothing to fear from decompression: it is as quick
  870.               whatever the compression level.
  871.             </p>
  872.                 </dd>
  873.                 <dt>
  874.                   <span class="term">Save defaults</span>
  875.                 </dt>
  876.                 <dd>
  877.                   <p>
  878.               <span class="guibutton">Save defaults</span>: If you click on this
  879.               button, your settings will be saved and can be used by other
  880.               savings by clicking on the <span class="guibutton">Load defaults</span>.
  881.             </p>
  882.                 </dd>
  883.               </dl>
  884.             </div>
  885.             <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
  886.               <table border="0" summary="Note">
  887.                 <tr>
  888.                   <td rowspan="2" align="center" valign="top" width="25">
  889.                     <img alt="[Note]" src="../images/note.png" />
  890.                   </td>
  891.                   <th align="left">Note</th>
  892.                 </tr>
  893.                 <tr>
  894.                   <td align="left" valign="top">
  895.                     <p>
  896.           Since PNG format supports indexed images, you have better reduce the
  897.           number of colors before saving if you want to have the lightest file
  898.           for the Web. See <a class="xref" href="gimp-image-convert-indexed.html" title="9.6.¬† Indexed mode">Section¬†9.6, ‚Äú
  899.     <span lang="en" xml:lang="en">Indexed mode</span>
  900.   ‚Äù</a>.
  901.         </p>
  902.                     <p>
  903.           Computers work on 8 bits blocks named ‚Äú<span class="quote">Byte</span>‚Äù.
  904.           A byte allows 256 colors. Reducing the number of colors below 256
  905.           is not useful: a byte will be used anyway and the file size will not
  906.           be less. More, this ‚Äú<span class="quote">PNG8</span>‚Äù
  907.           format, like GIF, uses only one bit for transparency; only two
  908.           transparency levels are possible, transparent or opaque.
  909.         </p>
  910.                     <p>
  911.           If you want PNG transparency to be fully displayed by Internet
  912.           Explorer, you can use the AlphaImageLoader DirectX filter in the
  913.           code of your Web page. See Microsoft Knowledge Base
  914.           <a class="xref" href="bibliography.html#bibliography-online-microsoft-kb294714" title="Microsoft Knowledge Base Article 294714">[<abbr class="abbrev">MSKB-294714</abbr>]</a>.
  915.           Please note, that this should not be necessary for
  916.           InternetExplorer 7 and above.
  917.         </p>
  918.                   </td>
  919.                 </tr>
  920.               </table>
  921.             </div>
  922.           </div>
  923.           <div class="sect3" lang="en" xml:lang="en">
  924.             <div class="titlepage">
  925.               <div>
  926.                 <div>
  927.                   <h4 class="title"><a id="file-tiff-save"></a>1.2.4.¬†
  928.         <span lang="en" xml:lang="en">Saving as TIFF</span>
  929.       </h4>
  930.                 </div>
  931.               </div>
  932.             </div>
  933.             <div class="figure">
  934.               <a id="id2590798"></a>
  935.               <p class="title">
  936.                 <b>Figure¬†6.5.¬†
  937.           <span lang="en" xml:lang="en">The TIFF Save dialog</span>
  938.         </b>
  939.               </p>
  940.               <div class="figure-contents">
  941.                 <a id="id2590810" class="indexterm"></a>
  942.                 <a id="id2590818" class="indexterm"></a>
  943.                 <a id="id2590827" class="indexterm"></a>
  944.                 <div class="mediaobject">
  945.                   <img src="../images/using/save-tiff-dialog.png" alt="The TIFF Save dialog" />
  946.                 </div>
  947.               </div>
  948.             </div>
  949.             <br class="figure-break" />
  950.             <div class="variablelist">
  951.               <dl>
  952.                 <dt>
  953.                   <span class="term">Compression</span>
  954.                 </dt>
  955.                 <dd>
  956.                   <p>
  957.               This option give you the opportunity to choose the compression
  958.               method that is appropriate for your image:
  959.             </p>
  960.                   <div class="itemizedlist">
  961.                     <ul type="disc">
  962.                       <li>
  963.                         <p>
  964.                   <span class="guilabel">None</span> : fast method, but resulting in
  965.                   a big file.
  966.                 </p>
  967.                       </li>
  968.                       <li>
  969.                         <p>
  970.                   <span class="guilabel">LZW</span> : The image will be compressed
  971.                   using the ‚Äú<span class="quote">Lempel-Ziv-Welch</span>‚Äù algorithm, a
  972.                   lossless compression technique. This is an old method,
  973.                   still efficient and fast. More informations at
  974.                   <a class="xref" href="bibliography.html#bibliography-online-wkpd-lzw" title="Wikipedia - LZW">[<abbr class="abbrev">WKPD-LZW</abbr>]</a>.
  975.                 </p>
  976.                       </li>
  977.                       <li>
  978.                         <p>
  979.                   <span class="guilabel">Pack Bits</span>
  980.                   : PackBits is a fast, simple compression scheme for
  981.                   run-length encoding of data. Apple introduced the PackBits
  982.                   format with the release of MacPaint on the Macintosh
  983.                   computer. A PackBits data stream consists of packets of one
  984.                   byte of header followed by data. (Source:
  985.                   <a class="xref" href="bibliography.html#bibliography-online-wkpd-packbits" title="Wikipedia - PackBits">[<abbr class="abbrev">WKPD-PACKBITS</abbr>]</a>)
  986.                 </p>
  987.                       </li>
  988.                       <li>
  989.                         <p>
  990.                   <span class="guilabel">Deflate</span>
  991.                 </p>
  992.                       </li>
  993.                       <li>
  994.                         <p>
  995.                   <span class="guilabel">JPEG</span>
  996.                 </p>
  997.                       </li>
  998.                     </ul>
  999.                   </div>
  1000.                 </dd>
  1001.                 <dt>
  1002.                   <span class="term">Save color values from transparent pixels</span>
  1003.                 </dt>
  1004.                 <dd>
  1005.                   <p> 
  1006.               With this option the color values are saved even if the pixels
  1007.               are completely transparent.
  1008.             </p>
  1009.                 </dd>
  1010.                 <dt>
  1011.                   <span class="term">Comment</span>
  1012.                 </dt>
  1013.                 <dd>
  1014.                   <p>
  1015.               In this text box, you can enter a comment which will be
  1016.               associated with the image.
  1017.             </p>
  1018.                 </dd>
  1019.               </dl>
  1020.             </div>
  1021.           </div>
  1022.         </div>
  1023.       </div>
  1024.     </div>
  1025.     <div class="navfooter">
  1026.       <hr />
  1027.       <table width="100%" summary="Navigation footer">
  1028.         <tr>
  1029.           <td width="40%" align="left"><a accesskey="p" href="ch05s03s07.html"><img src="../images/prev.png" alt="Prev" /></a>¬†</td>
  1030.           <td width="20%" align="center">
  1031.             <a accesskey="u" href="pt02.html">
  1032.               <img src="../images/up.png" alt="Up" />
  1033.             </a>
  1034.           </td>
  1035.           <td width="40%" align="right">¬†<a accesskey="n" href="gimp-using-web.html"><img src="../images/next.png" alt="Next" /></a></td>
  1036.         </tr>
  1037.         <tr>
  1038.           <td width="40%" align="left" valign="top"><a accesskey="p" href="ch05s03s07.html">3.7.¬†
  1039.       <span lang="en" xml:lang="en">Image Browser</span>
  1040.     </a>¬†</td>
  1041.           <td width="20%" align="center">
  1042.             <a accesskey="h" href="index.html">
  1043.               <img src="../images/home.png" alt="Home" />
  1044.             </a>
  1045.           </td>
  1046.           <td width="40%" align="right" valign="top">¬†<a accesskey="n" href="gimp-using-web.html">2.¬†
  1047.     <span lang="en" xml:lang="en">Preparing your Images for the Web</span>
  1048.   </a></td>
  1049.         </tr>
  1050.       </table>
  1051.     </div>
  1052.   </body>
  1053. </html>
  1054.