Reading GIF images in Win2k + Apache + PHP

I have a class that reads gif images & can then make jpeg or png thumbnails of the gif image, but it only seems to work on linux. Is there any way to open/convert the gif to some other graphic format so I can at least read the gif image in on windows? here's the current code I have for reading in file types, but the gif section blows up. Is there a way with something like readfile() or fopen() to get the information from a gif file? switch($type) { case "gif": $orig_img = imagecreatefromgif($filename); break; case "jpg": $orig_img = imagecreatefromjpeg($filename); break; case "png": $orig_img = imagecreatefrompng($filename); break; } Patrick