IE vs Firefox : Passing arguments to a GD image PHP script

I'm using PHP GD library to dynamically create an image from a set of arguments. In Firefox and Safari this works ok, but it seems that if I pass arguments to the script, in IE it won't display. Suggestions?

Seems I've fixed the problem. I was sending a lot of values which had high precision, when they could have been integers. If I round them first it works, so I guess IE has a smaller maximum number of characters allowed per argument, or somesuch.

There is a limit on the length of a GET request, which probably does vary by browser, but I'm wanting to say it's at least 1024 or 2048 characters. POST requests have no such limitations on size, but of course if you're attempting to use the GD script as an img src, GET is really your only option.