GIF, or Graphics Interchange Format, is a bitmap image format that was introduced by CompuServe. It has come into widespread usage on the World Wide Web due to its wide support and portability.
The format supports up to 8 bits per pixel for each image, allowing a single image to reference its own palette of up to 256 different colors chosen from the 24-bit RGB color space. It also supports animations and allows a separate palette of up to 256 colors for each frame.
However, in its infancy, GIF has met controversy. Allegedly unbeknownst to CompuServe at the time, the compression technique was patented in 1985 by Unisys. The two companies engaged in a copyright disagreement that carried into 1994, whereupon Unisys announced it would allow commercial properties to license the format for a small fee. In response to the disagreement, many developers wanted to boycott the use of GIF and use the PNG format instead.
However, obtaining support from the makers of web browsers and other software for the PNG format has proven to be difficult, and it was impossible to replace the GIF format.
GIF was one of the first two image formats commonly used on websites, the other one is the black and white XBM.
