Compress PNG images in your browser
Palette reduction and a real PNG optimiser, running on this device. Transparency survives intact.
or browse your device. Everything is processed on this device
No PNG to hand?
How to compress a PNG
One or a hundred. Drag them anywhere on the page. Nothing is uploaded.
Leave it at 256 for a lossless squeeze, or slide down and watch the estimate fall.
Drag the divider to compare before and after at full size, including the transparent areas.
Files are written straight from memory to your downloads, as PNG.
What is a PNG file?
PNG is a lossless raster format from 1996, built to replace GIF. It stores exact pixels rather than an approximation, it supports a full alpha channel so edges can fade to transparent, and every browser and image editor ever made will open it. That is why logos, icons, screenshots and UI exports are almost always PNG.
Lossless is the whole point and also the whole problem. A photograph saved as PNG keeps every sensor speck and every subtle gradient step, and there is no throwing any of it away, so the file lands five to ten times larger than the same picture as a JPG. PNG is the wrong format for a photograph. If it is a photo with no transparency, compress it as a JPG or a WebP instead.
Where PNG is right, the saving comes from the palette. A truecolour PNG spends up to four bytes on every pixel; an indexed PNG spends one byte plus a small colour table. Most screenshots and flat illustrations contain a few hundred distinct colours at most, so cutting the palette to 64 or 32 removes half the file without changing anything you can see.
PNG compression FAQ
Why is my PNG so large?
Almost always because it is truecolour when it does not need to be, or because it is a photograph. PNG never discards detail, so it stores every pixel in full, and a screenshot exported at 3x from a retina display carries nine times the pixels anyone will ever see. Lower the colours, cap the width, or accept that a photo belongs in JPG or WebP.
Is PNG compression lossless?
It depends on the setting. Left at 256 colours this tool is fully lossless: oxipng rebuilds the deflate stream and rewrites the row filters, and every pixel comes back identical. Lower the colours slider and it becomes lossy, because colours are being merged. The saving from lossless alone is usually 5 to 20%, which is why the slider exists.
Will transparency survive?
Yes. The alpha channel is carried the whole way through, quantisation treats transparency as part of the colour, and oxipng keeps the transparency chunk. Nothing here flattens onto white, which is the usual way a transparent PNG gets ruined.
How do I reduce a PNG under 1MB?
Turn on "Compress to a target size" and type 1000. We try the file as it is, then 256, 128, 64, 32, 16 and 8 colours, and stop at the largest palette that fits under your figure, telling you which one it landed on. If even 8 colours overshoots, we say so and hand back the smallest we managed rather than something unusable.
PNG or WebP?
WebP, for anything going on a website. Lossless WebP is typically 20 to 30% below an optimised PNG at identical pixels, it keeps the alpha channel, and every current browser reads it. Stay on PNG when the file has to open in older software, or when a client, a printer or an app store insists on it.
Should I use PNG for photos?
No. A photograph has no flat areas for lossless compression to exploit, so PNG stores it enormously. JPG at quality 80 or WebP at quality 80 will be a fraction of the size and look the same. Keep PNG for screenshots, logos, icons, diagrams and anything with hard edges or transparency.
Does dithering help or hurt?
Both. It hides banding in gradients by mixing neighbouring palette colours, at the cost of fine noise, and noise is exactly what PNG compresses worst. Leave it on for gradients and photographic content, turn it off for flat artwork where it only adds bytes.
Do my images get uploaded anywhere?
No. Decoding, quantising and oxipng all run in this tab as WebAssembly. Open your network tab and watch: after the page and the optimiser load, nothing carries your image, because your image never becomes a request.
Other compressors
Same format joins the queue. Anything else re-routes to its own tool.