JPEG
JPEG (pronounced "jay-peg") is designed for compressing either full-color or gray-scale images of natural, real-world scenes. It works well on photographs, naturalistic artwork, and similar material but not as well for lettering, simple cartoons, or line drawings.

JPEG is "lossy," meaning that the decompressed image isn't quite the same as the one with which you started. There are lossless image compression algorithms, but JPEG achieves much greater compression than is possible with lossless methods.

EyeBatch can write 24-bit RGB JPEGs or 8-bit grayscale JPEGs. Additionally, you can choose to write these as interlaced or progressive JPEGs. Progressive JPEGs are arranged so that smart decoders can display the image as it is transmitted across a slow network. EyeBatch also provides a JPEG quality setting that varies the amount of compression at the expense of image detail accuracy.

Because of its great compression, JPEG is by far the best choice for photographic images on the web. Also because of its compression, JPEG is a terrible choice for intermediate storage as you lose some image detail each time you write a JPEG image. If you are storing images for archival or as intermediate steps in a long process, one of the lossless formats is much better.

BMP
BMP (Bitmap) is Windows' native image format. BMP supports a simple form of compression called RLE (Run Length Encoding). RLE is good for Bitmaps that have pixels with the same color horizontally next to each other. In some cases, RLE compression can increase the size of a BMP. BMP is lossless and is fine for archival or temporary storage.

PNG
The PNG file format uses lossless data compression. It compresses better than LZW but does not compress photographic images as well as JPEG's Lossy compression. The PNG file format is geared to replace GIF as the Internet favorite, as it can store 24 bit images unlike GIF and has full alpha support (256 levels of transparency). GIF only has one level of transparency. PNG also has none of the licensing issues that GIF does. It is an excellent choice for image archival or temporary storage. Most modern web browsers support reading PNG format. For more information on PNG images, visit the article we wrote on the subject.

TIFF
TIFF is a standard image format used in both Macintosh and PC's. Tiff's can be read and saved in 24 or 8 bits. It also has a compressed format using LZW compression. EyeBatch will not read or write LZW compressed images due to licensing issues with Unisys Corporation.

PCX
PCX is an old format from the days when most displays were 8-bits and true color (24-bit) displays were unheard of. It can store images in 24 bits and 8-bit or less. It uses a simple run-length-encoding scheme similar to BMP-RLE. Compression is poor, but lossless. EyeBatch is able to read all PCX flavors and write PCX in 24 and 8 bit modes.

TGA
TGA is another old format. It supports a wide range of data formats, each apparently related to a specific Targa video card. Like PCX, data can be encoded with a simple run-length-encoding scheme: poor but lossless. EyeBatch reads many TGA flavors. It writes 24-bit and 8-bit TGA.

MetaFiles (WMF / EMF)
Metafiles are Window's based images that do not contain dimensions. The intention was that one could draw the image into any rectangle and it would scale itself accordingly. This is nice in some cases (clip art, for example) but not as nice in other cases. With the release of Windows 95, Microsoft discourages the use of WMFs.

With the release of Windows 95, Microsoft introduced the Enhanced Metafile (EMF). EMF adds sizing information to tell applications how large to draw the image.

PSD
PSD is the native format for Adobe Photoshop. EyeBatch provides reading for most PSD flavors: 16-bit channels, LAB and Multichannel are the known exceptions. Although EyeBatch will write 24-bit and 8-bit PSD files, there is little benefit in being able to write PSDs as Photoshop will read almost any format. Other formats provide better compression and greater support.

GIF
GIF is an internet standard for simple graphics. It stores a maximum of 256 colors (8-bit) and supports transparency. The GIF format uses a compression algorithm called LZW which is patented by Unisys corporation. As of version 2.0, EyeBatch obtained a license to support reading and writing GIF and LZW TIFF images. Due to the patent restrictions of GIF images, we recommend using PNG images. PNG is a great replacement to GIF as most modern browsers support it.

WBMP
WBMP is a relatively new image format that is a standard for black & white palm computing devices. These images are only black and white (not grayscale) and can be relatively small in filesize.