$users[$key]['avatar'] = array(
                    "tiny" => AvatarUtility::Format($row['user_avatar'], 25, 25),
                    "thumb" => AvatarUtility::Format($row['user_avatar'], 50, 50),
                    "small" => AvatarUtility::Format($row['user_avatar'], 75, 75),
                    "medium" => AvatarUtility::Format($row['user_avatar'], 100, 100)