GIF Image

The Graphics Interchange Format (GIF) is a bitmap image format developed by a team at online service provider CompuServe and released in 1987. Since then, it has spread across the World Wide Web due to its broad support and portability between applications and operating systems.

The format supports up to 8 bits per pixel per image, allowing a single image to reference its own palette of up to 256 different colours chosen from the 24-bit RGB colour space. It also supports animations and allows a separate palette of up to 256 colours per frame. These palette limitations make GIF less suitable for reproducing colour photographs and other images with colour gradients, but it is well suited to simpler images such as graphics or logos with solid colour areas.

GIF images are compressed using the Lempel-Ziv-Welch (LZW) lossless data compression technique to reduce file size without degrading visual quality. This compression technique was patented in 1985. The dispute over the licence agreement between the software patent holder, Unisys, and CompuServe in 1994 stimulated the development of the Portable Network Graphics (PNG) standard. By 2004, all relevant patents had expired.