How to compress a PNG
- Drop one or more PNG files on the box above.
- PNG colors is set to 256. Try 128 or 64 for screenshots and icons to save even more.
- Compare the before and after sizes in the table, and download the files or a ZIP.
How PNG compression works
PNG is lossless, so simply re-saving a PNG barely changes its size. The real savings come from color quantization: most screenshots, logos and illustrations use far fewer than the 16 million colors a full PNG can hold. This tool analyses the image, picks the best 256 (or fewer) colors with a median-cut algorithm, and saves an 8-bit palette PNG, the same approach popular PNG optimisers use. Files typically shrink by 50–70% and transparency, including soft edges, is preserved.
Palette PNGs suit flat graphics best. Photos and smooth gradients can show banding with few colors; convert those to JPG or WebP instead. If the result looks wrong, pick "Lossless" to keep every color.
Everything runs in your browser, so images are never uploaded.
FAQ
Is PNG compression lossless?
Lossless mode is, but saves little. The 256-color mode is lossy in color but keeps sharp edges and transparency, and is usually invisible on graphics.
Why is my compressed PNG not much smaller?
The image may already be optimised, or it is a photo with many colors. Try fewer colors, or convert it to WebP.
Does it keep the transparent background?
Yes. Transparency, including partial transparency, is stored in the palette.