How does JPG compression work?
JPEG reduces file size by discarding detail the human eye barely notices, especially subtle color changes. PixPress re-encodes your image using the mozjpeg encoder with trellis quantization and optimized progressive scans, which produce a smaller file at the same visual quality.
Use the quality slider to balance size and fidelity — values around 75–85 are usually indistinguishable from the original for photos and web graphics.
Frequently Asked Questions
What quality should I use?
For web photos, 75–80 is a good default. Use 85+ if you need maximum fidelity.
Why is my already-optimized JPG barely smaller?
Images exported by modern tools already use advanced encoding, so there is little room left. The biggest gains come from camera originals or high-quality exports.
Are my images uploaded?
No. All processing happens locally in your browser.
Is it free?
Yes, unlimited and with no signup.