GIF

GIF (Graphics Interchange Format) is a bitmap image format for pictures that use 256 (or fewer) distinct colors (though there is a workaround for this limitation). and animations that use 256 (or fewer) distinct colors per frame. GIFs are compressed files, and are employed specifically to reduce the amount of time it takes to transfer images over a network connection. The format was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web.

Related Topics:
Bitmap - Image format - Workaround - Animation - Compressed - CompuServe - 1987 - World Wide Web

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A GIF file employs lossless data compression so that the file size of an image may be reduced without degrading the visual quality (provided the image fits into 256 colors). The GIF format's 256-color limitation makes it unsuitable for photographs, though losslessly compressed photographs tend to be unacceptablly large for the web anyway. On the other hand the lossy JPEG (Joint Photographic Experts Group) format does badly on sharp transitions like those in diagrams, producing highly visible artifacts and little file-size reduction. Therefore GIF is normally used for diagrams, buttons, etc., that have a small number of colors, whilst the JPEG format is used for photographs.

Related Topics:
Lossless data compression - JPEG (Joint Photographic Experts Group)

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Many software developers were caught by surprise when it was revealed that the GIF format had been patented by Unisys, and that they would have to pay royalties for writing programs that generated (or displayed) GIF files. The desire for a comparable format with fewer legal restrictions (as well as fewer technical restrictions such as the number of colours) led to the development of the PNG (Portable Network Graphics) standard. Although the Unisys patent has since expired, PNG is still touted as a technically superior alternative, and has become the third most common image format on the web.

Related Topics:
Unisys - PNG (Portable Network Graphics)

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