OptiPNG: Advanced PNG Optimizer
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.
OptiPNG 0.7.4 (stable)
OptiPNG Hg (development)
A use-after-free vulnerability in the palette reduction code has been
discovered in the versions
If you use any of these versions, please upgrade to version
at your earliest convenience.
(A fix was previously issued in version 0.7.3,
but that one, ironically, failed to address the option
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.