On a basic unix/linux mail server, you create a file called .forward in your home directory. All mail can then be run through a program as specified in this file.

Since this feature of unix can be used for mischief, many systems only allow you to only use a restricted set of programs as the filter. This is not a problem as long as a program called procmail is on the approved list. You can easily hook up your program so that procmail will run your perl program. See the docs for procmail. Also, procmail can help with some other problems that you might run into, such as the need to do file locking.

Image::Magick is a reasonable choice, it should work.

The challenge will be to get some people to read your response. I receive many mail bounces like the ones that you want to create, but I filter them out, because they are aimed at spammers who have forged a return address that ends up getting forwarded to me. To deal with the large number of these, I use aggressive mail filters that remove almost all such autoreplies.