Image functions

Im trying to modify a poll script to not use the hard coded image files and use php's image functions. On the file that will be outputing the poll graphics, I tried at the top of the page -> header("Content-type: image/png"); and header("Content-type: image/jpeg"); For some reason, when the page is viewed, the only thing that gets output to the browser is the url of the page.... I tried using one of the examples on php.net image create routines and its still doing the same thing.. Here is a snip <?php /* * THIS HAS TO GO HERE FOR THE IMAGE BARS */ header("Content-type: image/jpeg"); $pollID = $HTTP_POST_VARS['pollID']; $voteID = $HTTP_POST_VARS['voteID']; <------snip---------> If I comment out the header call, Im back to normal... Im running PHP 4.1.2 with GD support Any thoughts Thanks