Pngcrush is a easy-to-use, command line optimizer for PNG files. pngcrush and other tools for manipulating PNG (Portable Network Graphics) and MNG (Multiple-image Network Graphics) files.

usage:
1. pngcrush [options] infile.png outfile.png
2. pngcrush -e ext [other options] files.png ...
3. pngcrush -d dir [other options] files.png ...

The license of this software is Free, you can free download and free use this image utility software.