I was in the same boat you are, a few months back. I write Perl for a living, and I'm not entirely bad at it but I had a terrible time with GD. Honestly, I didn't really give it a lot of effort, because while looking around the net for help, I found ImageMagick.org.

They provide some excellent Linux software (maybe other platforms too) with C and Perl APIs. Highly recommended as their software can do just about anything with an image.