PDFConvertersOnline.comHow to compress a PNG
- Add PNG files such as screenshots, logos, icons or exported designs.
- Keep the default quality for a 256-color palette, or lower it for even fewer colors. Target size is also available.
- Compress, zoom in with the before/after slider, and save the new PNGs.
Why PNG needs a different approach
PNG is lossless: it stores every pixel exactly, which is why it is the format of choice for text, interface screenshots and artwork with hard edges. The downside is that the usual trick for photos, lowering a quality number, does not exist. Squeezing the same pixels harder barely changes the size.
What does work is reducing how many different colors the picture uses. A typical exported graphic contains tens of thousands of slightly different shades. Mapping them onto a well-chosen palette of 256 colors or fewer, and saving the result as an indexed PNG, often cuts the file by more than half while looking the same at normal viewing size. That is what this tool does.
How the quality slider maps to colors
| Slider | Colors | Good for |
|---|---|---|
| 95–100% | All (lossless) | When every pixel must stay exact |
| 75% (default) | 256 | Most logos, UI screenshots, diagrams |
| 50% | about 64 | Flat illustrations, simple icons |
| 25% and below | 16 or fewer | Very simple graphics; gradients start to band |
Transparency stays intact
The palette includes see-through and half-see-through colors, so a logo with soft edges on a transparent background comes out with the same clean edges. Nothing is flattened onto white. That is the main reason to compress a PNG instead of converting it to JPG, which cannot store transparency at all.
When to switch to JPG instead
If your PNG is really a photo (a camera shot someone saved as PNG, for example), a palette won't help much because photos contain smooth gradients everywhere. When the image has no transparent pixels, tick Convert PNG to JPG for smaller files and it will usually shrink many times over. The option is ignored for files that do have transparency, so a cut-out logo is never ruined by accident. For one-off conversions there is also PNG to JPG and PNG to WebP.
Typical results
Screenshots of apps and websites, charts, diagrams and flat logos usually shrink the most, because they contain large areas of the same color. Illustrations with soft shadows shrink less, and photographs saved as PNG shrink least. The results list shows each file's old and new size and the percentage saved, so you can see at a glance which files benefited. Any file that would get bigger is left untouched.
More ways to use this tool
Frequently asked questions
Is this lossless PNG compression?
Only at the very top of the slider. At the default setting the colors are reduced, which is lossy, but the change is rarely visible on logos, screenshots and flat artwork.
Will my transparent background turn white?
No. Transparent and semi-transparent pixels are kept. Only the optional JPG conversion would remove them, and it is skipped for any image that has transparency.
Why do gradients look striped after compressing?
A smooth gradient needs many shades. Raise the slider for more colors, or use the lossless setting for that file.
Can I get a PNG under a certain size?
Yes. Choose Target size: the tool tries 256, 128, 64, 32 and 16 colors, and only if none fits does it reduce the pixel dimensions as well.
Does it work on screenshots from my phone?
Yes, and they usually shrink well because interfaces are made of flat areas and text.
Can I use the compressed PNG as a website icon or logo?
Yes. It is a normal PNG that every browser supports. For a set of favicon sizes, see Favicon Generator.