Compress PNG
Compress a PNG and keep it a PNG. The file gets much smaller, and the transparent background and crisp edges stay.
How the files you choose are handled is set out in the privacy policy.
How to compress a PNG
- Tap Choose PNG files and select one or more.
- Leave the colours on 256 for the best result, or choose fewer for a smaller file.
- Press Compress PNG and save.
How a PNG gets smaller
An ordinary PNG stores red, green, blue and transparency for every pixel: four numbers each, with millions of possible colours. Most pictures use far fewer colours than that.
This PNG compressor finds the 256 colours that represent the picture best and builds a palette from them. Each pixel then stores one small number, the position of its colour in the palette. A quarter of the data, before the usual PNG packing is even applied.
The size in pixels does not change, and the result is still a normal PNG that opens everywhere.
What to expect
| Kind of picture | Typical result | Visible change |
|---|---|---|
| Screenshot of an app or web page | Half the size or less | Usually none |
| Logo, icon, diagram | Much smaller | None. With 256 colours or fewer nothing is lost at all |
| Illustration with soft shading | Half the size or less | Slight grain in gradients |
| Photograph saved as PNG | A third of the size | Fine grain. A JPG would be smaller still |
If a picture already has 256 colours or fewer, they are kept exactly and the tool tells you nothing was lost. If a file cannot be made smaller, it is handed back unchanged and listed as such.
Transparency is kept
Each palette colour has its own transparency, so cut-out logos, soft shadows and rounded corners survive. Fully transparent areas stay fully transparent, which matters when the picture sits on a coloured page.
The two settings
Colours to keep
256 is right for almost everything. Flat artwork such as icons, charts and pixel art often looks identical at 64 or 32, and the file shrinks further. If areas of colour start to look blotchy, go back up.
Smooth out gradients
With fewer colours, a smooth fade can turn into visible bands. This option mixes neighbouring palette colours in a fine pattern, called dithering, so the fade looks smooth again. It adds a little grain and a little size. Turn it off for flat artwork, where it is not needed.
PNG or something else?
PNG is the right format for sharp edges and transparency. For photographs it is the wrong one: a photo saved as JPG is several times smaller than the best PNG. If your PNG is really a photo, PNG to JPG will save far more than compressing it. For photos already in JPG, use compress image.
Questions
Does compressing a PNG lose quality?
If the picture has more than 256 colours, some are merged with their nearest neighbour. On screenshots and artwork this is rarely visible. With 256 colours or fewer nothing is lost.
Will my transparent background stay transparent?
Yes. Transparency is stored for each palette colour, including partly see-through edges and shadows.
Why did my file not get smaller?
It was probably compressed this way already, or it is very small. The tool returns such files unchanged.
Is the result still a normal PNG?
Yes. Palette PNGs are part of the PNG standard and open in every browser, phone and image program.
Can I make the picture smaller in pixels too?
Use the resize image tool first, then compress the result here.