Portable Network Graphics (PNG) format


    Developed as a patent-free alternative to GIF, Portable Network Graphics (PNG) format is used for lossless compression and for display of images on the World Wide Web. Unlike GIF, PNG supports 24-bit images and produces background transparency without jagged edges; however, some Web browsers do not support PNG images.

    When you export artwork to PNG format, the PNG Options dialog box appears. Set the desired options, and click OK:

    Resolution

    Determines the resolution of the rasterized image. (See Combining vector graphics and bitmap images.) Higher resolution values result in better image quality but larger file sizes.

    Note: Some applications open PNG files at 72 ppi, regardless of the resolution you specify. In such applications, the dimensions of the image will be altered. (For example, artwork saved at 150 ppi will be over twice as large as artwork saved at 72 ppi.) Therefore, only change the resolution when you know the target application supports non-72-ppi resolutions.

    Color

    Specifies a color for filling transparency. Choose Transparent to preserve transparency, White to fill transparency with white, Black to fill transparency with black, or Other to select another color for filling transparency.

    Anti-Alias

    Removes jagged edges in the artwork by supersampling it. Deselecting this option helps maintain the hard edges of line art when it is rasterized.

    Interlaced

    Displays low-resolution versions of the image as the file downloads in a browser. Interlacing makes download time seem shorter, but also increases file size.