How this compressor works
Each format is compressed with the method that suits it best:
- JPG files are re-encoded with MozJPEG, an encoder from Mozilla designed to squeeze JPGs smaller than standard encoders at the same visual quality.
- PNG files have their colours reduced to a palette of up to 256 and are saved as a compact palette PNG. Transparency is kept. Choose “Lossless only” to keep every pixel and let oxipng find the smallest encoding instead.
- WebP files are re-encoded with Google’s libwebp at the quality you choose.
You can mix formats in one batch. The quality slider applies to JPG and WebP files; the colour setting applies to PNG files.
How much smaller will images get?
It depends on how the image was saved. Photos straight from a phone or camera are often saved at very high quality and shrink by half or more. Screenshots and graphics saved as PNG often shrink by 60–80% when their colours are reduced. Images that were already optimised for a website may only shrink a little, and if compressing would make a file bigger, your original is kept.
Choosing the settings
- Quality 75% is the default and suits photos for websites, email and chat.
- Quality 85–90% keeps more fine texture, useful for portfolios and product photos.
- 256 PNG colours looks identical to the original for almost all screenshots, logos and illustrations.
- Lossless only shrinks a PNG without changing a single pixel. Savings are smaller, typically 5–50%.
Click the small preview next to any result to compare it with the original side by side.
Compressing vs resizing
Compression keeps the same width and height and stores the pixels more efficiently. If an image is far larger than it needs to be, for example a 4000-pixel photo shown 800 pixels wide on a web page, resizing it first saves far more space. Use the image resizer for that, then compress the result.
Privacy
Your images never leave your device. The compression code downloads once, then runs in your browser. Location and camera data stored in photos is not copied into the compressed files.
Questions
Does compressing an image reduce its quality?
JPG and WebP compression removes fine detail you are unlikely to notice at the default setting. PNG compression reduces the number of colours, which is invisible on most graphics and screenshots. Use the preview to compare before you download.
Will my images keep their format?
Yes. A JPG stays a JPG, a PNG stays a PNG and a WebP stays a WebP, so they work everywhere the original did.
Why did a file come back the same size?
If an image is already well compressed, re-encoding it would make it bigger. In that case the converter keeps your original and tells you so.
Can I compress many images at once?
Yes. Select or drop as many as you like. They are processed one after another, and you can download them individually or all together as a ZIP file.
Last reviewed 30 October 2026