Image Compressor
Shrink JPG, PNG and WebP — with real palette quantisation for PNG.
About this tool
Compress JPG, PNG and WebP in your browser. Palette quantisation halves PNGs or better, and the before/after sizes are real. No uploads, no sign-up.
How to use it
- Select a JPG, PNG or WebP image. The original size and pixel dimensions appear immediately.
- Pick an output format. For PNG, choose “Smart palette” and set how many colours to keep — this is the step that produces the large savings.
- Compare the real before/after byte counts (and the colour count actually used), then download.
- Turn dithering off for flat UI screenshots and on for photos and gradients.
Frequently asked questions
How does the PNG compression actually work?
Smart palette mode reduces the image to an 8-bit indexed palette (up to 256 colours) with error-diffusion dithering, then re-encodes it with deflate. That is the same principle TinyPNG is built on, and it is why the savings are far larger than re-encoding a PNG losslessly. Everything runs locally — the image is never uploaded.
Why did my file get bigger?
Re-encoding an already optimised file can add bytes, and “Lossless” mode only repackages the existing pixels. When the result is larger we say so instead of reporting a fake saving — switch to Smart palette or WebP.
Does palette mode lose quality?
It loses colour precision, not resolution: gradients can band and photos can show slight dithering noise. Text and flat UI stay sharp. The colour slider trades size against fidelity, and the measured drop for a 2880×1800 screenshot at 256 colours was about 35 dB PSNR — visually very close.
Everything on this page runs in your browser. QuickTools has no upload endpoint, no account system and no analytics script.