Compress PNG images
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Shrink screenshots, logos and graphics while keeping them PNG, with transparency intact.
PNG stays PNG on this page, so transparent backgrounds, sharp text and crisp UI edges survive. The main trick is colour reduction: most screenshots, icons and illustrations use far fewer than the millions of colours PNG can hold, so we rebuild each image with a palette of up to 256 colours and repack it with a lossless optimiser. Typical savings on graphics are large. Everything runs locally in your browser.
How to use Compress PNG
- Drop PNG screenshots, logos, icons or diagrams.
- Quality 75 (the default) uses a 256-colour palette; 40–59 uses 128 colours and below 40 uses 64 for the smallest files. At 90 or more the PNG is optimised losslessly with every colour kept.
- Compress, check the results, and download them individually or as a ZIP.
What happens to quality, size and metadata
Palette reduction is lossy, but on the right images you won’t see it: text, flat colours, charts and UI screenshots look identical with 256 colours. Smooth gradients and photographs are where you may see banding, since we don’t add dithering noise. For those, use quality 90 or above for lossless optimisation, or convert the photo to JPG or WEBP.
Transparency is preserved, including semi-transparent pixels, because the palette includes alpha. Images that already have 256 colours or fewer are repacked without any loss.
- Test files
- 30
- Average input
- 14.7 MB
- Average output
- 4.8 MB
- Size change
- 67% smaller
- Time per file
- 3.9 s
About PNG
| Full name | PNG |
|---|---|
| Full name | Portable Network Graphics |
| Introduced | 1996 |
| Defined by | W3C · ISO/IEC 15948 |
| Compression | Lossless |
| Transparency | Yes |
| Animation | Yes |
| Largest size | 2,147,483,647 × 2,147,483,647 px |
| Chrome / Edge | Yes |
| Safari | Yes |
| Firefox | Yes |
| Windows | Yes |
| iPhone / iPad | Yes |
| Android | Yes |
| Typical use | Screenshots, logos, icons, diagrams and any image that needs a transparent background. |
PNG PNG is a lossless image format published by the W3C in 1996 and later as ISO/IEC 15948. Every pixel is kept exactly, and it supports full transparency, which makes it ideal for screenshots, logos and text. Photos saved as PNG are usually several times larger than as JPG.
Sources for this table
- www.w3.org/TR/png-3/
- www.iso.org/standard/29581.html
- caniuse.com/apng
- developer.mozilla.org/en-US/docs/Web/Media/Guides/Formats/Image_types
- developer.android.com/media/platform/supported-formats
Browser support data: caniuse.com, CC BY 4.0.
Without this site
Windows and macOS have no PNG compressor built in. Saving from Paint or exporting from Preview writes a standard PNG without palette reduction, which can even make the file bigger. Image editors offer “save for web” style exports with colour counts, and developers use command-line optimisers in build pipelines. For quick, private batches, this page does both steps at once.
Troubleshooting
- Gradients look stepped. Raise quality to 90 for lossless mode, or keep such images in another format.
- A photo saved as PNG. Palette reduction won’t help much. Convert it to JPG or WEBP for a real reduction.
- Pixel art. It usually has few colours already, so it shrinks losslessly. Check that no colours shifted at low quality.
- Already optimised. If our result isn’t smaller, you get the original file back.
Questions and answers
How do I reduce PNG file size without losing quality?
Set quality to 90 or higher: the PNG is then optimised losslessly, keeping every pixel exactly while repacking the data more tightly. Savings are modest. For bigger savings, the default 256-colour palette usually looks identical on screenshots and graphics, even though it is technically lossy.
Does compressing a PNG keep transparency?
Yes. The reduced palette includes transparency levels, so fully transparent backgrounds, semi-transparent shadows and anti-aliased edges are kept. The output is still a regular PNG that works anywhere a PNG did, in browsers, design tools, slides and documents alike, with nothing to install on the viewer’s side.
Why is my PNG still large after compression?
It is probably a photo or contains large smooth gradients, which need many colours and don’t compress well losslessly. PNG is the wrong format for photos; convert to JPG (no transparency) or WEBP (with transparency) to make it much smaller. Reducing dimensions with a max size also helps.
What does the quality setting do for PNG?
It sets how many colours remain: 60–89 keeps up to 256, 40–59 up to 128, and below 40 up to 64. At 90 and above nothing is reduced and only lossless optimisation runs. Fewer colours means smaller files, with more risk of visible banding.