What you're asking for sounds impossible, but in case I'm wrong (heh) let's review.

• Client wants 'watermarked' images available for web visitors.
• Client doesn't want to preprocess the images.
• Web host doesn't permit the installation of binaries.

Therefore, you need to either come up with a pure-Perl solution or switch web hosting companies.

I've used convert on Linux to great success, but your post doesn't indicate whether you're on Linux or, if you are, whether convert is available. If not, perhaps the documentation at Image::Magick web site will tell you if it's pure Perl or not.

Good luck!

--t. alex
Life is short: get busy!