Comment 2 for bug 669457

I wrote a test script which verifies correctness and ran it against a few thousand PNG files in my system, which all worked fine:

  find /usr/share/ -name '*.png' | ./optipng-check

I forwarded the test script to upstream:
https://sourceforge.net/tracker/?func=detail&aid=3100839&group_id=151404&atid=780916