in reply to hijacking a module constructor

If your GD modules provide an OO-interface (I don't know if they do or don't) then you might just want to make your own class that inherits from GD and override the method in question.

Check out perltoot in the docs or Damian Conway's book.

Hanlon's Razor - "Never attribute to malice that which can be adequately explained by stupidity"

In Section Seekers of Perl Wisdom