public static function getUrl($photo, $sizeShort)
 {
     if (!FlickrPhotoHA::hasSize($photo, $sizeShort)) {
         return false;
     } else {
         if ($sizeShort != FlickrPhotoHA::SIZE_ORIGINAL_SHORT) {
             return "http://farm" . $photo->farm . ".staticflickr.com/" . $photo->server . "/" . $photo->id . "_" . $photo->secret . "_" . $sizeShort . ".jpg";
         }
         return "http://farm" . $photo->farm_id . ".staticflickr.com/" . $photo->server_id . "/" . $photo->image_id . "_" . $photo->original_secret . "_" . $sizeShort . ".jpg";
     }
 }