JPG and GIF explained
JPEG is a lossy image format designed for photographs. It works by discarding detail the human eye is least likely to notice, particularly in colour and in smooth gradients, which is why it compresses photos far better than it compresses text or line art.
GIF is a 1987 format limited to a 256-colour palette per frame, with support for simple animation and one fully transparent colour. Its longevity is cultural rather than technical — nothing about it is efficient by modern standards.
- Where JPG files come from
- Digital cameras, phone screenshots on Android, and essentially every photo on the pre-2015 web.
- Where GIF is used
- Reaction images, simple UI animations, and screen recordings shared in chat.