Problems with file_get_contents() and local PHP file

Hey. My server is running PHP 4(Not actually my server so I don't know the exact version) and I'm having trouble with getting an image from a PHP file. I have a file, flash_frames.php, which outputs an image composed of the combination of a bunch of other images. Another file, flash.php, takes this image and chops it up into frames and then animates it in a flash file. The problem is that originally this system was developed to be used with PHP 5, and used fopen() and stream_get_contents() to retrieve the image file from flash_frames.php. I thought I could just replace both of those with file_get_contents(), but it appears to fail when doing so. A quick test confirmed that file_get_contents(), when used locally, returns the PHP source as opposed to the output of the file. I didn't originally code this (I am but an inheritor who is learning PHP as he goes :P), so I'm at a loss for what should be done to fix this. I considered just converting the file into a function that returns the image, but I cannot find out how to return an image (Or convert the image to a string of bytes as the original code expected it to be). Any help is greatly appreciated. :) -Mike Original code for retrieving image: //Replaces res_viewer to flash_frames since they both take the same arguments $img=rawurldecode($img); $fl_imgsrc=str_replace('/res_viewer.php?','/flash_frames.php?scale='. $scale.'&',rawurldecode($img)); //Grabs the generated image set up for the flash preview $handle = fopen($fl_imgsrc, "rb"); $contents = stream_get_contents($handle); $fl_map = new SWFBitmap($contents); fclose($handle);