GIF Graphics Interchange Format
CompuServe, 1987. 8-bit (256 colors), lossless, supports animation. Patent on LZW compression led to PNG's creation in 1996. Today mostly for short animated memes.
Technically outdated: 256 colors ⇒ poor photographic quality, lossless but inefficient compression, large files for animation. Slack/Discord/Reddit "GIF" buttons usually display MP4 files (much smaller, same experience). APNG (Animated PNG) + WebP/AVIF animation are technical successors, but "GIF" has survived as a cultural term. Pronunciation debate: "jif" (creator Steve Wilhite) vs "gif" with hard G (rest of the world).