private function executePOST($method_args)
 {
     $this->validate_args($method_args);
     $this->check_for_authentication();
     $header = $this->build_header();
     $url = $this->get_request_url();
     $r = new Http_Request2($url, Http_Request2::METHOD_POST);
     $r->setHeader('X-Verify-Credentials-Authorization', $header);
     $r->addPostParameter('key', TwitPic_Config::getAPIKey());
     foreach ($method_args as $arg => $val) {
         $r->addPostParameter($arg, $val);
     }
     $res = $r->send();
     if ($res->getStatus() == 200) {
         if (strlen($res->getBody() > 0)) {
             return $this->respond($res->getBody());
         } else {
             return true;
         }
     } else {
         throw new TwitPicAPIException($res->getBody());
     }
 }