> I discovered that in Internet Explorer, the printer-friendly page  
> comes up with the correct logo in the browser. But, when "Print" (or  
> "Print Preview") is clicked, the browser makes another httpd call to  
> the site. This call contains NO context info: No user, group,  
> $_SESSION, referrer info, nothing. Therefore, my program cannot  
> select the correct logo.

I seem to have resolved my problems by adding this to my code in a couple of places:

  header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
  header('Cache-Control: no-store, no-cache, must-revalidate');
  header('Cache-Control: post-check=0, pre-check=0', FALSE);
  header('Pragma: no-cache');
 
  cache_clear_all();

This doesn't help the problem with the $user context disappearing (I solved that by creating a variable using the user's ip address and storing the info I need there - very crude, but works), but by forcing the browser not to cache the image I am dynamically creating.

Thanks for the suggestion.

-ron