public function getResourceThumbnails(array $uris, $defaultAllowed = false)
    {
        $result = array();
        $url = self::makeUrl();
        $postString = Util::query_suffix(array("uri" => $uris, "defaultAllowed" => $defaultAllowed));

        $response = $this->service->makeRequest($url, array(200), 'POST', $postString, true, 'application/x-www-form-urlencoded');
        $data = json_decode($response['body']);
        if (isset($data)) {
            foreach ($data as $thumbnail) {
                $result[] = ResourceThumbnail::createFromJSON($thumbnail);
            }
        }
        return $result;
    }