Excellent answer davidrw!

a few replys:

1. Initial code included the debug line, but it didn't tell me anything useful so I removed it to simplify the problem
2. Noted :)
3. I committed the sin of "editing the code for publication" and deleted the fullstop. It was a .jpg.
4. The code you supplied works fine and is an excellent starting point for the problem I need to solve.
5. Noted and much appreciated

This is my first venture into using Image Magick. It was in the context of showing Great GrandFather how wonderfull Perl is and how he could save so much time with a small Perl tool used to brand pictures to be put on a web site. The result wasn't quite as impressive as I'd hoped :). Honour will be regained however - thank you.