Graphics Interchange Format (GIF):

256 color format that was made popular by CompuServe until controversy over licensing drove the creation of the PNG format.

GIFs are still popular because they support animation. Very popular for emoticons and…err…other animation requirements where a video is too big.

GIFs have a maximum of 256 colors. They contain no internal resolution information and will size at the default for each application, usually 72dpi.