/**
 \defgroup ITKPNG Module ITKPNG 
 This module contains the third party <a
href="http://www.libpng.org/pub/png/libpng.html/">Portable Network Graphics
(PNG)</a> image file format library. 
 \par Dependencies:
 \li \ref ITKZLIB 
 \dot 
 graph "ITKPNG" { 
 "ITKPNG" -- "ITKZLIB"; 
 } 
 \enddot 
 */