psydk.org
PngOptimizer
- Cleans your PNG files of useless or wrong information.
- Reduces your PNG files weight.
- Converts into PNG other lossless image formats (BMP, GIF, TGA).
- Supports animated PNG (APNG).
- Creates easily available PNG screenshots.
- Offers a simple and productive user interface.
Do you like PngOptimizer? Please consider making a donation: 
Installation from PPA (Ubuntu)
sudo add-apt-repository ppa:psydk/pngoptimizer
sudo apt update
sudo apt install pngoptimizerDownload
Windows (64 bits)
Download PngOptimizer version 2.7 x64 (zip 184 kB)
Debian, Ubuntu (64 bits)
Download PngOptimizer version 2.7 x64 (deb 205 kB)
More details in this review: 
Other downloads
- Windows x86 (32-bit)
- Download PngOptimizer version 2.7 (zip 160 kB)
PngOptimizerCL: a command line version of PngOptimizer
Note: Ubuntu/Debian package already comes with PngOptimizerCL, but you can download it separately here.
- Windows x64
- Download PngOptimizerCL version 2.7 (zip 134 kB)
- Windows x86
- Download PngOptimizerCL version 2.7 (zip 118 kB)
- Linux x64 (built on Ubuntu 20.04)
- Download PngOptimizerCL version 2.7 (tgz 130 kB)
PngOptimizer and PngOptimizerCL are distributed under the terms of the GNU General Public License (GPL).