Compare software

pngquant vs Image Optimizer: catalog facts
pngquant	Image Optimizer
Free Free and open source; the CLI is under GPL-3.0-or-later with some parts under HPND and…	Free Free and open source under the MIT licence.
Windows, macOS, Linux, Command line	Linux
Large file size reductions with preserved transparency Adaptive dithering with less noise	Lossless compression with identical pixels Processes a whole folder at once
Command line only; graphical use needs a separate front end Lossy, so not suited to images that must stay pixel-exact	Only PNG and JPEG Overwrites the original files in place
Downloadable app	Downloadable app
Open source	Open source
License: GPL-3.0-or-later	License: MIT
No account needed	No account needed
Works offline	Not stated if it works offline
Official website Full listing and sources Checked October 1, 2026	Official website Full listing and sources Checked October 1, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.