GIF?

GIF (Graphics Interchange Format) is an 8-bit-per-pixel bitmap image format using a palette of up to 256 distinct colors from the 24-bit RGB color space. The format was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability. It also supports animations and even allows a separate palette of 256 colors for each frame.