How to compress a PNG without losing quality

PNG is a lossless format. Unlike JPEG or WebP, it never throws pixels away to save space — it stores an exact recipe for rebuilding the image, pixel for pixel. That's the whole point of the format, and it's why "compress PNG without losing quality" is almost a tautology: done properly, a compressed PNG decodes to a picture that is identical to the original.

So where does the saving come from? A PNG can simply be re-encoded more efficiently. The tool re-packs the same pixels, drops redundant data the original encoder left behind, trims an oversized colour palette down to the colours actually used, and strips metadata you don't need. None of that alters the image — it just writes a leaner file that rebuilds exactly the same picture.

Because the optimisation is lossless, you don't need a quality slider at all — there's nothing to trade away. You just re-export a tighter copy:

• Open the PNG compressor and drop your file in — screenshots, logos, icons and exported graphics all work.
• Let it re-encode. It re-packs the pixels, prunes the palette and removes leftover metadata to write a smaller file.
• Preview to confirm it looks identical (it will), then export and download the lighter copy.

Everything runs on your device — you can disconnect from the internet after the page loads and it still works, which is the plainest proof your file is never uploaded. Need to shrink several at once? The full set of compression tools handles batches and exports them together.

Here's the honest limit: lossless compression only shrinks a PNG so far, and how far depends entirely on the content. Flat graphics — screenshots, logos, icons, line art, text, large areas of solid colour — compress beautifully, because they contain the kind of repetition a lossless encoder can exploit.

A photograph is the opposite. Almost every pixel differs slightly from its neighbours, so there's little repetition to squeeze, and a photo saved as PNG stays enormous — often several times larger than it needs to be. The fix isn't a better PNG; it's a different format. Converting the photo to JPG or WebP uses lossy compression to drop detail your eye won't miss, and the file collapses to a fraction of the size. That is a genuine trade — you give up PNG's perfect fidelity — but for a photo on the web it's almost always the right call.

A few habits make PNG compression reliable:

• Match the format to the content. Keep PNG for anything flat and crisp; reach for a lossy format for photos. The PNG format guide covers where it shines and where it doesn't.
• Let the palette shrink. If a graphic only uses a handful of colours, a well-optimised PNG stores just those, which can cut the size sharply with zero visible change.
• Keep transparency in mind. Lossless PNG optimisation preserves the alpha channel, so anything transparent stays transparent — only switching to a format like JPG would flatten it.

Working with photos as well as graphics? The companion guide on compressing images without losing quality walks through choosing quality levels and formats across JPG, WebP and AVIF.