[Zope] advice to track graphics rendering in DTML or python(script)

[Trevor Toenjes]

> cant that be named
> http://zope/images/header.gif?uid=Alkj9876
> then you can ask for the id with
> <dtml-var uid>
> there is also some way to get the URL with all the parameters that where
> used. However I do not find it.

I considered that, but I do not control the formatting.  Another system is
rendering the HTML.  It is being rendered to zope as
http://zope/images/header.gif?Alkj9876.  And I dont want to render the
graphic unless it has an ID.
I guess this is almost like a banner system.

How do I change the browser's REQUEST for header.gif to redirect to another
GIF?