All image compression falls into two categories: lossless and lossy. Understanding the difference is the key to choosing the right format and settings for every image you work with.
| Lossless | Lossy | |
|---|---|---|
| How it works | Finds patterns and encodes them efficiently | Discards data the eye won't miss |
| Quality | Pixel-perfect — zero quality loss | Some data permanently removed |
| File size reduction | 10-30% | 50-90% |
| Reversible? | Yes — original can be reconstructed | No — loss is permanent |
| Best for | Screenshots, logos, text, archives | Photos, web images, email |
| Formats | PNG, Lossless WebP | JPG, Lossy WebP, AVIF |
Use lossless when: every pixel matters (screenshots, medical images, archival), you need to edit the image repeatedly, or the image has text/sharp edges that lossy compression would blur.
Use lossy when: file size matters more than perfection (websites, email, social media), the image is a photograph, or you need dramatic size reductions.
A 1920×1080 screenshot saved as PNG (lossless) might be 847 KB. The same image compressed as lossy WebP at 80% quality becomes 156 KB — 82% smaller — with no visible quality difference to the human eye. That's the power of understanding when to use each compression type.
Try it yourself: use our free image compressor to experiment with different quality settings and see the difference in real time with the before/after comparison slider.