How Image Compression Works
Image compression reduces file size by removing detail. Learn how lossy and lossless methods differ.
Published 2026-02-20
In this guide
Short answer
Compression reduces an image's file size by encoding it more efficiently. Lossy compression (like JPEG) discards visual detail; lossless (like PNG) keeps all detail at a larger size.
Lossy vs lossless
Lossy methods trade quality for smaller files and are best for photos. Lossless methods preserve every pixel and are best for graphics and text.
Practical tips
For the web, use an image compressor at 70–80% quality, resize to the display size, and consider modern formats like WEBP for even smaller files.