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Compress PNG

Optimise PNG files losslessly with OxiPNG — identical pixels, smaller file.

How to compress PNG

Drop your PNG files onto the panel above and press Compress. Whole folders are fine, and the results download individually or as one ZIP.

There is nothing to configure, because PNG optimisation is lossless: the quality slider does not apply and the pixels come out bit-for-bit identical. Once the run finishes, the before/after slider lets you confirm that for yourself at full resolution.

Everything runs inside this page as WebAssembly, so your files are never uploaded. That is why there is no size limit and no queue, and why the tool keeps working if you go offline.

How PNG compression works

PNG compression is lossless, so there is no quality to trade away. Optimising a PNG means finding a smaller encoding of exactly the same pixels: better row filters, a tighter Deflate stream, and the removal of redundant chunks. Decode the result and it is bit-for-bit identical to the original.

Encoder: OxiPNG, a modern lossless PNG optimiser written in Rust, compiled to WebAssembly.

How much smaller PNG files get

Savings depend entirely on how the PNG was written. Screenshots and exports from design tools often shrink 20–60%; a PNG that a build pipeline already optimised may barely move at all.

There is no quality setting, and there is no risk: the pixels cannot change. Running the optimiser twice is harmless.

When to convert instead

If the PNG contains a photograph, the real saving is a format change, not optimisation. Converting it to JPG or WebP commonly removes 80% or more of the file size with no visible difference. Keep PNG for logos, screenshots, diagrams, and anything needing transparency.

Frequently asked questions

Does compressing PNG reduce quality?

No. PNG optimisation is mathematically lossless — the output decodes to exactly the same pixels as the input, just stored more efficiently. There is no setting that could degrade it.

How much can PNG be compressed?

Savings depend entirely on how the PNG was written. Screenshots and exports from design tools often shrink 20–60%; a PNG that a build pipeline already optimised may barely move at all.

How do I compress PNG to a KB limit?

Switch Compression to To a file size and type the limit, or start from a page with the target preset: 20 KB, 50 KB, 100 KB, or 200 KB. The tool searches quality levels automatically and keeps the best result that fits.

Compress PNG or convert it?

If the PNG contains a photograph, the real saving is a format change, not optimisation. Converting it to JPG or WebP commonly removes 80% or more of the file size with no visible difference. Keep PNG for logos, screenshots, diagrams, and anything needing transparency.

Finish the job

Common follow-ups, one click from here. Your image stays on your device between tools.