Package pngcrush

http://pmt.sourceforge.net/pngcrush/

pngcrush is a commandline optimizer for PNG (Portable Network Graphics) files.
Its main purpose is to reduce the size of the PNG IDAT datastream by trying
various compression levels and PNG filter methods. It also can be used to
remove unwanted ancillary chunks, or to add certain chunks including gAMA,
tRNS, iCCP, and textual chunks.

Version: 1.8.13