Good general introduction to Perl/Tk is the book Learning Perl/Tk by Nancy Walsh. Good online demo is widget available from your command line if you have installed Tk module. Tk::JPEG includes some samples as well, it's basically just another image type though.

There is also the GUI Programming section of Code Catacombs. Finally, there is a newsgroup comp.lang.perl.tk which tracks the ptk mailing list.

Beyond those things I'm not sure what you're looking for, could you elaborate?