What you want to do really screams for a templating engine, as the only thing that changes per document is the data from the web form.

Personally, I wouldn't create the images with GD but create PDFs from LaTeX, as LaTeX gives a lot of flexibility and a nice layout. The sooner you go away from overlaying text onto a pretty picture, the easier it will be.

The only problem is, of course, if the pretty background picture is something you cannot change/influence. Then, TeX is out of the window, as you'd then have to describe the fields as locations to TeX, which is no more fun than describing them to GD.

Have a look at TT2, which is, AFAIK, a general templating system (opposed to a templating system geared for HTML) and what TeX output you can get from there. The rest, spawning off LaTeX to create a temporary PDF and redirecting the user to that PDF file is then fairly simple.

perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ;    # The  
$d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider
($c = $d->accept())->get_request(); $c->send_response( new   #in the
HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' #  web
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