Need Quick Script (AJAX) - EXPERT NEEDED

Hi, I need a quick PHP script that does the following: 1. A page will have some photo thumbnails on it. See attached example. Each photo will have its own unique ID. 2. Clicking on a thumbnail should make an AJAX call and add the clicked photo's ID to the PHP session - an array will contain all the photos selected. $_SESSION['photos'][] = $photo_id; It would also apply some kind of a style to the thumbnail that has been clicked (green background). See attached sample. 3. Clicking a green-background/selected photo again would remove the green background and remove the photo from the PHP session. Notes: > The script should use jQuery to make the AJAX calls. [login to view URL] ? > Use latest version of jQuery.