How does PNG compression work?
A standard 24-bit PNG can store over 16 million colors, but most images — screenshots, logos, illustrations — use only a few thousand. PixPress analyzes your image and builds a custom palette of up to 256 colors, then remaps every pixel to the nearest palette color.
Because each pixel now references a palette index instead of a full color value, the file becomes dramatically smaller. Selective dithering keeps gradients smooth, and the alpha channel is preserved with premultiplied-alpha processing so transparent edges stay crisp.
Is it safe?
Yes. The compression engine is a small WebAssembly module that runs entirely on your device. Your PNG never leaves your browser, which also means there is no waiting for uploads and no server to store your files.
Frequently Asked Questions
Will my PNG lose transparency?
No. The encoder preserves the full alpha channel, including semi-transparent edges.
How much smaller will my PNG be?
UI screenshots and flat illustrations typically shrink 60–80%. Smooth photographic gradients see smaller gains.
Is there a file size limit?
Images up to roughly 50 MB on desktop and 20 MB on mobile work reliably. Very large images may exceed browser memory.
Do I need to sign up?
No. The tool is free, unlimited, and requires no account.