Compress / PNG
Compress PNG Images Online
Reduce PNG file sizes with an adjustable colour palette. Transparency survives; flat graphics survive it well and photographs do not. Bulk upload supported.
Why Compress PNG Files?
Keep transparency
Unlike JPG, PNG compression preserves alpha channel transparency for logos, icons, and graphics.
Faster page loads
Optimized PNGs load faster on websites, improving user experience and SEO rankings.
Email friendly
Compressed PNGs stay under email attachment limits. On a screenshot or a logo the palette reduction is invisible at the sizes email is used for.
Adjustable palette
Control the compression level to find the right balance for your needs.
What each quality setting actually costs
PNG is a lossless format, so this slider does something different from the JPG one. It reduces how many distinct colours the image is allowed to use, then stores that result losslessly. Flat graphics and screenshots survive that very well because they contain few colours to begin with. Photographs do not, which is why the two rows below behave so differently.
| Measure | Quality 100 | Quality 75 | Quality 60 | Quality 30 |
|---|---|---|---|---|
| Screenshot with transparency | 56 KB | 46 KB | 39 KB | 35 KB |
| Photograph | 2,791 KB | 1,249 KB | 1,198 KB | 930 KB |
| Colours allowed | 256 | 109 | 57 | 9 |
| Transparency kept | Yes | Yes | Yes | Yes |
Screenshot measured on this site's own 1776 x 1690 interface capture, photograph on a 3840 x 2160 image. Because the slider controls palette size rather than a JPEG-style quality, its effect depends heavily on the picture: a screenshot with few colours barely changes, while a photograph loses smooth gradients to visible banding well before the bottom of the range. If your source is a photograph, JPG or WEBP will beat any PNG setting here.
Questions
How does compressing a PNG even work? Is it not lossless?
PNG is lossless, so there is no quality dial inside the format the way there is in JPEG. What the slider actually controls is how many colours the image is allowed to keep. Full quality re-encodes at maximum effort and changes no pixels. Below that, the image is quantized to a palette, and the slider is mapped cubically rather than linearly because that is where the encoder responds: every palette from about 129 to 256 colours produces a near-identical file, so a linear slider left most of its travel doing nothing.
How much smaller will my PNG get?
It depends entirely on the picture, more so than with JPEG. Our own measurement on a photograph went from 69.6 KB at full quality to 27.5 KB at 70 and 3.9 KB at 10. A flat graphic went from 5.9 KB to 2.8 KB to 0.8 KB across the same settings. Notice that full quality and 85 came out identical on both: at the top of the range there is nothing left to remove without touching the colours.
When does compressing a PNG barely help?
When the image is a photograph. PNG has to store every pixel exactly, and reducing a photo to a few hundred colours produces visible banding long before it produces a small file. If your PNG is a photograph, converting it to JPG or WebP will beat compressing it as PNG by a wide margin. If it is a logo, a screenshot or a diagram, palette reduction is exactly the right tool and the savings are large.
Will transparency survive?
Yes. The alpha channel is preserved through quantization, so a logo with a transparent background stays transparent.
Are my files uploaded?
Compression runs on our server, unlike most conversions on this site which run in your browser. Files are processed in memory and discarded when your download starts, and compressing counts against the daily limit.
This one comes to our server
A browser cannot do this one, so the file is uploaded, held in memory, converted, returned and discarded. Nothing is written to disk and there is no account to attach it to.
What the privacy policy saysFurther reading
Explainer8 minPNG compression is lossless, so why does compressing a PNG lose somethingTwo different operations share one button. One rearranges bytes and changes nothing. The other throws away colours, and on a photograph it barely saves anything either.Benchmark11 minI ran a real photo corpus through every format this site outputsPNG, JPG, WebP, AVIF, GIF and PDF, measured on the same images with the same pipeline, including the PSNR that shows which ones actually kept the pixels.Optimize your PNGs
Smaller files, transparency intact, and the table above says what the colours cost.