<graphics, file format> /gif/, occasionally /jif/ (GIF, GIF 89A) A standard for digitised images compressed with the LZW algorithm, defined in 1987 by CompuServe (CIS). Graphics Interchange Format and GIF are service marks of CompuServe Incorporated. This only affects use of GIF within Compuserve, and pass-through licensing for software to access them, it doesn't affect anyone else's use of GIF. It followed from a 1994 legal action by Unisys against CIS for violating Unisys's LZW software patent. The CompuServe Vice President has stated that "CompuServe is committed to keeping the GIF 89A specification as an open, fully-supported, non-proprietary specification for the entire on-line community including the World-Wide Web". Filename extension: .gif. File format (ftp://peipa.essex.ac.uk/ipa/info/file-formats). {GIF89a specification (http://asterix.seas.upenn.edu/Graphics Interchange Formatmayer/lzw_gif/gif89a.html)}. See also progressive coding, animated GIF. (2000-09-12)

<graphics, file format> (GIF89a) A variant of the GIF image format, often used on World-Wide Web pages to provide moving icons and banners. The GIF89a format supports multiple "frames" that give the impression of motion when displayed in sequence, much like a flip book. The animation may repeat continuously or play once. Animated GIFs aren't supported by earlier web browsers, however the first frame of the image is still shown. There are many utilities to create animated GIFs from a sequence of individual GIF files. There are also utilities that will produce animated GIFs automatically from a piece of text or a single image. One problem with this format is the size of the files produced, as they are by definition a sequence of individual images. Apart from minimising the number of frames, the best way to decrease file size is to assist the LZW compression by using blocks of solid colour, avoid dithering, and use fewer colours. If areas of an image don't change from one frame to another, they don't need to be redrawn so make the area a transparent block in the second frame. (1999-08-01)