How can I "flip" an image using PHP?

Question

Possible Duplicate:
How to resize an image using PHP?

Here's what I've tried:

$image = "images/20100609124341Chrysanthemum.jpg"; 
$degrees = 40; 
// Content type 
header('Content-type: image/jpeg'); 
// Load 
$source = imagecreatefromjpeg($filename);
// Rotate 
$rotate = imagerotate($source, $degrees, 0);
// Output 
imagejpeg($rotate); 

...But I get no output. Can anyone tell me what's wrong with this?

Answer 1

Using the image rotate function: http://php.net/manual/en/function.imagerotate.php