libpng, Graphics, Portable Network Graphics libraru for OpenVMS

From Wikipedia: libpng is the official PNG reference library 
(originally called pnglib). It is a platform independent 
library that contains C functions for handling PNG images. 
It is developed by Guy Eric Schalnat, Andreas Dilger, 
Glenn Randers-Pehrson and others. 

libpng is dependent on zlib.

For information:

  <http://libpng.sourceforge.net/>
  <http://en.wikipedia.org/wiki/Libpng>