Compress Volcano PNG images.
Compressed with Synopsis:
    optipng [options] files ...
Files:
    Image files of type: PNG, BMP, GIF, PNM or TIFF
Basic options:
    -?, -h, -help	show the extended help
    -o <level>		optimization level (0-7)		[default: 2]
    -v			run in verbose mode / show copyright and version info
Examples:
    optipng file.png						(default speed)
    optipng -o5 file.png					(slow)
    optipng -o7 file.png					(very slow)
Type "optipng -h" for extended help.