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pngquantOptiPNG
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 zlib licence.

Windows, macOS, Linux, Command line Windows, Command line
  • Large file size reductions with preserved transparency
  • Adaptive dithering with less noise
  • Lossless recompression of PNG files
  • Converts BMP, GIF, PNM and TIFF to optimized PNG
  • Command line only; graphical use needs a separate front end
  • Lossy, so not suited to images that must stay pixel-exact
  • Command line only, no graphical interface
  • Lossless only, so savings are smaller than lossy tools
Downloadable app Downloadable app
Open source Open source
License: GPL-3.0-or-later License: Zlib
No account needed No account needed
Works offline Works offline

Checked October 1, 2026

Checked October 2, 2026

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