1) Free software programmed in C
Found on
https://www.crosswordclues.com/clue/pngcrush
pngcrush is a free, open source command-line utility for optimizing PNG image files. It reduces the size of the file losslessly — that is, the resulting `crushed` image will have the same quality as the source image. The main purpose of pngcrush is to reduce the size of the PNG IDAT data stream by trying various combinations of compression met.....
Found on
http://en.wikipedia.org/wiki/Pngcrush
No exact match found.
