Compress PNG Without Losing Transparency
Short answer
Shrink a PNG below with transparency fully intact — the alpha channel is never touched, only the colours are reduced. Runs in your browser, nothing uploaded.
Drop a PNG here
or drop your file here.
Nothing is uploaded — it stays on your device.
Runs in your browser — your file is never uploaded.
Add an image, then press "Compress image".
The usual worry about compressing a transparent PNG is that it will come back with a white box behind it. That happens when a tool converts to JPEG somewhere in the pipeline, because JPEG has no alpha channel at all and has to composite transparency onto a background.
This tool never does that. A PNG in gives a PNG out, and the alpha byte of every pixel is copied through completely untouched. Only the red, green and blue values are reduced to fit your chosen colour budget.
Keeping alpha out of the quantisation matters for more than just the fully transparent areas. Anti-aliased edges — the semi-transparent pixels around a logo's curve — are what make it look smooth against any background. Quantise those and the edge goes visibly jagged, which is exactly the artefact that makes a compressed logo look cheap.
How to compress a PNG without losing transparency
- 1Add the PNG. Drop it in — it stays on your device.
- 2Pick a colour budget. 256 is safe; 64 suits logos and flat art.
- 3Compress. Alpha is preserved exactly as it was.
- 4Download. A smaller PNG, transparency intact.
Frequently asked questions
Will semi-transparent edges stay smooth?+
Yes. The alpha channel is excluded from quantisation entirely, so anti-aliased edges keep every intermediate transparency value and stay smooth against any background.
Can I compress a transparent PNG to JPG instead?+
You can, but you will lose the transparency — JPEG has no alpha channel, so transparent areas are filled with white. Keep it as a PNG whenever the transparency matters.