As said, definitely go with Image::Magick. I don't believe there are any native perl modules that can deal with PNG or JPEG (after searching CPAN).

If you're feeling frisky you could try code up the community a tool to read JPEG files natively in perl and write them out to 24-bit bitmap format, and then code up a module to read/write PNG files from bitmaps.

But since nobody else has done that yet, I don't believe it is trivial. I've written a perl module to deconstruct bitmap files, though. Neat stuff if you get into it.

--
perl -e "print qq/just another perl hacker who doesn't grok japh\n/"
simeon2000|http://holdren.net/