JPEG compression
1992 (ITU T.81)
A standard for compressing photographs to a tenth of their size or less, by discarding detail the eye barely sees. It made storing and sending pictures practical.
How it began
Digital pictures were huge for 1980s disks and modems. The Joint Photographic Experts Group, set up by standards bodies, worked from 1986 on a common way to compress photos. The standard was approved in 1992.
How it works
The image is split into 8×8 pixel blocks. Each block is turned into a set of frequencies, and fine detail and colour, which the eye notices least, are stored with less precision or dropped. The rest is packed tightly.
Why it mattered
Pictures shrank enough to fit on memory cards and travel over the internet. Digital cameras, the web, email and phones all rely on it.
Limits and what replaced it
Each save loses some detail, and heavy compression shows blocks. Photographers who want everything use raw files.
Today
The most common image format in the world; newer formats such as HEIF and AVIF compete with it.