Compress your PNG
Reduce the size of your PNGs without visible quality loss.
Drop your files here
Related tools
Compress PNG losslessly in your browser
PNG is a lossless format, which means a naive compressor cannot make a PNG smaller without losing visual fidelity. Filzy uses a different approach: libimagequant (the engine behind pngquant) reduces the colour palette to 256 colours or fewer using perceptual quantization, which preserves how the image looks while shrinking the file by 50 to 70 percent. The output remains a valid PNG that opens in every viewer, but it is encoded as an indexed PNG instead of a 32-bit one. Transparency is preserved. The whole pipeline runs in your browser via WebAssembly, so the original PNG never leaves your device.
Files stay on your device
Compression runs in a Web Worker via a Rust core compiled to WebAssembly. The image bytes never touch a server, no thumbnail or copy is sent.
Lossless palette quantization
libimagequant analyses the image perceptually and reduces it to 256 colours or fewer. The visual result is indistinguishable from the source for most photos and graphics.
Batch process whole folders
Drop dozens of PNGs at once. Filzy compresses them in parallel using your CPU cores and packages the result as a single ZIP archive.
How to compress PNG with Filzy
- 1
Drop your PNG files
Drag images in, or click to pick them. The tool accepts standard 8-bit and 16-bit PNGs, with or without an alpha channel.
- 2
Pick a quality preset
Aggressive (max savings, ~70%), Balanced (the sweet spot at ~50%), or High quality (~30%) for archival or print use cases.
- 3
Filzy quantizes locally
The Rust core decodes the PNG, builds an optimised palette via pngquant's algorithm, and re-encodes as an indexed PNG. Transparency is preserved.
- 4
Download single or as ZIP
Save individual PNGs, or click Download all to grab a ZIP. Files chained to other Filzy tools (Convert, Remove EXIF) also stay local.