Package optipng

PNG optimizer and converter

http://optipng.sourceforge.net/

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.
General Commands
Command Description
optipng Optimize Portable Network Graphics files