public function insertPhotoEntry($photo, $uri = null)
    {
        if ($uri instanceof Zend_Gdata_Photos_AlbumEntry) {
            $uri = $uri->getLink(self::FEED_LINK_PATH)->href;
        }
        if ($uri === null) {
            require_once 'Zend/Gdata/App/InvalidArgumentException.php';
            throw new Zend_Gdata_App_InvalidArgumentException(
                    'URI must not be null');
        }
        $newEntry = $this->insertEntry($photo, $uri, 'Zend_Gdata_Photos_PhotoEntry');
        return $newEntry;
    }