PNG Compressor
Shrink PNG files with 256-color quantization (the pngquant technique) right in your browser — typically 50–70% smaller with transparency preserved.
Drop PNG files here
or — multiple files welcome. Nothing is uploaded; conversion happens on your device.
Files are processed entirely in your browser — never uploaded, never stored. Large photos convert in about a second each; the first HEIC file loads a small decoder module.
How it works
PNG compression here is the real thing — the pngquant technique: the palette is reduced to 256 optimally-chosen colors with dithering. Screenshots, UI graphics, and logos routinely shrink 50–70% while staying visually identical, transparency included.
- Drop the PNGs above — quantization runs locally (the encoder loads on first use).
- Check the before/after sizes; use Compare at actual size to inspect gradients, the one place 256 colors can band.
- Download the compressed PNGs — still standard PNGs, openable everywhere.
Original PNG vs Quantized PNG
| Original PNG | Quantized PNG | |
|---|---|---|
| Colors | Up to 16.7M | 256 (optimally chosen) |
| Screenshots / UI | Baseline | 50–70% smaller, looks identical |
| Photos / gradients | Baseline | Smaller but may band — use JPEG/WebP instead |
| Transparency | Preserved | Preserved |
Tip: This is the same approach TinyPNG charges API fees for — running it locally costs nothing and your images stay on your machine.
Frequently asked questions
How does PNG compression work here?
It reduces the palette to 256 optimally-chosen colors with dithering — the same technique as pngquant/TinyPNG. For screenshots, UI graphics, and logos the result is typically 50–70% smaller and visually identical. Transparency is fully preserved.
When does PNG quantization look bad?
On photos and smooth gradients, where 256 colors can band visibly. For photographic content, JPEG or WebP compression is the better tool — this one shines on graphics.
Are my images uploaded to a server?
No. Conversion runs entirely in your browser using its built-in image engine — files never leave your device, which also makes it faster than upload-based converters and safe for private photos.