How image compression works
A photo straight from a phone camera is often 3 to 8 MB, far more than a website, email or online form needs. Compression makes the file smaller by storing the picture more efficiently. Lossy formats such as JPG and WebP throw away detail your eye barely notices; lossless PNG keeps every pixel and only packs the data tighter.
The quality slider controls how much detail is kept. Around 75–80% usually looks the same as the original while being 60–80% smaller.
Which quality should you choose?
| Use | Suggested quality | Typical result for a 4 MB photo |
|---|---|---|
| Printing or archiving | 90% | about 1.5–2 MB |
| Website or blog | 75–80% | about 300–600 KB |
| Email or WhatsApp | 65–75% | about 200–400 KB |
| Online form with a strict limit (e.g. 100 KB) | 50–60%, and resize too | under 100 KB |
The exact size depends on the picture: photos with lots of fine detail (grass, crowds) compress less than plain backgrounds.
How to get under a size limit like 50 KB or 100 KB
Admission portals, job sites and government forms often ask for a photo or scan under a fixed size. If lowering the quality alone isn't enough, the picture simply has too many pixels. Pick a smaller size in the Maximum width option (800 or 1024 pixels is plenty for most forms), or set an exact size with the Image Resizer, then compress. Two small steps give a much sharper result than one very low quality setting.
Common problems
- The PNG barely got smaller. PNG is lossless, so screenshots and logos shrink only a little. If the image is a photo, convert it with PNG to JPG or the WebP Converter for a much smaller file.
- The result looks blocky. The quality is too low. Raise it to 70% or more and reduce the dimensions instead.
- Transparent areas turned white. JPG has no transparency. Keep the image as PNG or WebP if you need a see-through background.
Is it safe for private photos?
Yes. The compression runs inside your browser using your own device. Your photos are never uploaded, so ID cards, documents and family pictures stay with you.