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OptiPNGImage Optimizer
Free

Free and open source under the zlib licence.

 Free

Free and open source under the MIT licence.

Windows, Command line Linux
  • Lossless recompression of PNG files
  • Converts BMP, GIF, PNM and TIFF to optimized PNG
  • Lossless compression with identical pixels
  • Processes a whole folder at once
  • Command line only, no graphical interface
  • Lossless only, so savings are smaller than lossy tools
  • Only PNG and JPEG
  • Overwrites the original files in place
Downloadable app Downloadable app
Open source Open source
License: Zlib License: MIT
No account needed No account needed
Works offline Not stated if it works offline

Checked October 2, 2026

Checked October 1, 2026

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