OptiPNG: Advanced PNG Optimizer

OptiPNG is a PNG optimizer that recompresses image files to a smaller size, without losing any information. This program also converts external formats (BMP, GIF, PNM and TIFF) to optimized PNG, and performs PNG integrity checks and corrections.
If you wish to learn how PNG optimization works, or to know about other similar tools, see the PNG-Tech article A guide to PNG optimization.

See the Security Information section below.


Security information

A use-after-free vulnerability in the palette reduction code has been discovered in the versions 0.7, 0.7.1 and 0.7.2. If you use any of these versions, please upgrade to version 0.7.5 at your earliest convenience.

(A fix was previously issued in version 0.7.3, but that one, ironically, failed to address the option -fix. Many thanks to Gynvael Coldwind and Mateusz Jurczyk for the report!)

If you use the opngreduc module programmatically, ensure that you are using the latest version.


    OptiPNG is open-source software, released under the zlib license.
    The contributing authors, i.e. the people who contributed code to OptiPNG.
    The program revision history.
    The author is indebted to all the people who helped the OptiPNG development.


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