This update for pngcheck fixes the following issues:

pngcheck was updated to 3.0.3:

Version 3.0.1:

*  fixed a crash bug (and probable vulnerability) in large (MNG) LOOP chunks

Version 3.0.2:

* fixed a divide-by-zero crash bug (and probable vulnerability)
  in interlaced images with extra compressed data beyond the
  nominal end of the image data (found by "chiba of topsec alpha
  lab")