define('SESSION_NAME', 's'); // Default of vBulletin is "s".
define('COOKIE_PREFIX', 'bb'); //Default of vBulletin is "bb".
define('COOKIE_TIMEOUT','1800'); //Set the same with your vB timeout, in second
define('ALBUM_FOLDER','/image/'); //Your Album Folder WITH trailing slash
this code and the old code
are both in session.php