Image compression
Also known as: compress image, reduce image size, shrink photo file size
Image compression shrinks a photo’s file size by removing redundant or less-visible data. Lossy compression (JPEG, WebP) drops fine detail for big savings; lossless compression (PNG) keeps every pixel but saves less. It is the fastest way to make images smaller for sharing, email, or the web.
- Lossy saves more but discards detail; lossless keeps every pixel
- JPEG/WebP/AVIF are lossy; PNG is lossless
- Compress from the original to avoid stacking quality loss
Lossy vs lossless
Lossy compression — used by JPEG, WebP, and AVIF — discards detail the eye is unlikely to notice, so files can shrink to a fraction of the original. Push it too far and you see blocky artifacts or banding. Lossless compression — used by PNG — repacks the same pixels more efficiently, so the image is bit-for-bit identical but the savings are smaller.
For photos, lossy at a high quality setting usually gives the best balance. For screenshots, logos, and line art with flat colors and text, lossless (PNG) keeps edges crisp.
When to compress
Compress before emailing or uploading when a file is too large, when a page needs to load faster, or when you are storing many images and want to reclaim space. Re-saving a JPEG repeatedly compounds quality loss, so compress from the original where you can.