Compress JPG, PNG and WebP images in your browser and compare the before and after sizes instantly.
Open toolCompress PNG Images
Optimise PNG files losslessly, reduce colours, or convert to WebP — with transparency preserved.
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How to use Compress PNG
- Upload your PNG files.
- Choose lossless, a reduced colour count, or convert to WebP/JPEG.
- Preview the result to check for banding before downloading.
- Batch several files and download them together as a ZIP.
About this tool
Compress PNG optimises PNG files while keeping them lossless by default, or shrinks them further by reducing the colour palette. You can also convert to WebP for much smaller files, all while preserving transparency.
Recommended settings
- For screenshots and flat graphics, lossless or WebP works best.
- Reducing to 256 or 128 colours often shrinks illustrations dramatically.
Supported formats
Input: PNG. Output: PNG, WEBP, JPEG.
Quality & file size
Lossy formats (JPEG, WebP, AVIF) trade detail for smaller files as you lower the quality; PNG stays lossless regardless of the slider. The tool always shows the original and result sizes so you can judge the trade-off, and it never recommends a result that is larger than your original as an “optimisation”.
Privacy
Every image is decoded, transformed and re-encoded entirely in your browser using the Canvas API and a Web Worker. Files are never uploaded, are not stored in localStorage, and are cleared from memory when you remove them or close the page.
Common issues & limitations
- Lowering the colour count can band gradients and soften anti-aliased edges.
- Browser PNG encoding is lossless only; it cannot match specialised tools on every file.
- All processing happens on your device; nothing is uploaded, so very large batches are limited by your available memory.
Frequently asked questions
How is PNG compression different from JPEG?
PNG is lossless, so a quality slider does not apply. This tool instead re-encodes losslessly, optionally reduces the number of colours, or converts to WebP for bigger savings.
Will reducing colours hurt my image?
It can. Fewer colours mean smaller files but can cause banding in gradients and soft edges. Preview the result before downloading.
Does transparency survive?
Yes. PNG output keeps the alpha channel. If you convert to JPEG, transparency is flattened onto a background colour you choose.
Are my images uploaded to a server?
No. Every image is decoded, processed and encoded entirely inside your browser using the Canvas API. The files never leave your device and are discarded when you close the page.