A GIF file is an image stored in the Graphical Interchange Format (GIF) which is pronounced by "jiff". It can contain up to 256 indexed colors, and the color palette can be a predetermine group of colors or match the colors in the image. GIF files are stored in lossless format, which means that sharpness of the image is not affected by GIF compression.
The GIF format was first published by CompuServe in 1987, although it was last modified in 1989. In plenty of other words, GIF is slightly older than the Rest Of The internet and is older than around 35% of the United States population.