If you have a blank in the file name, and you use a local URL, this function works. Not so with a fully qualified URL
<?php
$url = 'RAY_rgb 300x100.jpg';
$img = ImageCreateFromJPEG($url);
// WORKS PERFECTLY
$url = 'http://www.example.com/RAY_rgb 300x100.jpg';
$img = ImageCreateFromJPEG($url);
// FAILS Warning: imagecreatefromjpeg() [function.imagecreatefromjpeg]: gd-jpeg: JPEG library reports unrecoverable error
?>