Images
What is Lossy compression?
Also called lossy.
Lossy compression reduces file size by permanently discarding some information, aiming to keep the result looking or sounding similar.
How it works
Lossy formats throw away information that people are unlikely to notice. For images, that usually means fine color variation and texture within small areas. JPEG, lossy WebP, AVIF and HEIC all use this trade-off to make photographs much smaller.
Lower quality settings usually save more bytes but can create blur, blockiness or halos around sharp edges. Compare exports at the size people will actually view them: artifacts visible when zoomed to 400 percent often disappear at normal size.
Lossy vs lossless
| Feature | Lossy | Lossless |
|---|---|---|
| Original recoverable | No | Yes |
| Size saving on photos | Large | Modest |
| Examples | JPEG, lossy WebP, AVIF, MP3 | PNG, ZIP, FLAC |
| Best for | Final photos to share | Graphics, text, masters |
Pixels removed by resizing are also lost, even when the output format is lossless.
A practical example
For an email attachment, a moderately compressed photo may look identical on screen while shrinking from 6 MB to 600 KB, well under an upload limit.
What to watch out for
Increasing the quality setting on an already damaged image won’t recover lost detail. Keep an original copy for future editing and export from it each time.
Tools you can use
- Image Compressor · Cut file size with a visible quality trade-off
- Image Converter · Change an image from one format to another
- Compress PDF · Shrink the images, keep the text sharp
- Image Resizer · Scale to a size, a percentage or a platform preset
Go a little deeper
- How to compress a PDF for email or an upload limit
- How to make an image 300 DPI
- How to reduce image size without losing visible quality
- How to resize an image for a website
Common questions
What quality setting should I use for JPEG?
Around 75 to 85 percent suits most photos for the web and email. Above 90, files grow quickly with little visible gain; below 60, blocks and blur become noticeable.
Can lossy compression be reversed?
No. The discarded information is gone. Converting to a lossless format afterwards only preserves the current, already compressed version.
Is lossy compression bad?
Not for delivery. Nearly every photo, video and song you stream is lossy. It becomes a problem only when files are edited and re-saved many times.