I've never heard of graphicsmagick - forked from ImageMagick in 2002, nice! I guess they provide the standard convert command? If so, the first step is figuring that out. I use Image/PerlMagick myself for some things, but I have to study the docs any time I really need to do something. But anything you can do at the commandline (convert) should translate conceptially to the Perl API, and in fact that's what I do usually - get it working in the CLI then translate it over to the Perl using what I've learned.