Print info and check PNG, JNG, and MNG files

Current version

Revision: 1

Recent formula history

Nikolaus Wittenstein Add descriptions to all remaining homebrew packages
Xu Cheng pngcheck: fix sha256
Xu Cheng pngcheck: use sha256
Xu Cheng pngcheck: modernize and add test
Andrei Polushin build pngcheck utilities using the provided Makefile.

Formula code at GitHub