code: def _get_image_url(self, image_id):
          
          gce = self._connect()
          filter = "name eq %s" % image_id
          request = gce.images().list(project=self._project_id, filter=filter)
          response = self._execute_request(request)
          response = self._wait_until_done(response)
  
          image_url = None
          if "items" in response:
              image_url = response["items"][0]["selfLink"]
  
          if image_url:
              return image_url
          else:
              raise ImageError("Could not find given image id `%s`" % image_id)
docs: Gets the url for the specified image. Unfortunatly this only works
          for images uploaded by the user. The images provided by google will
          not be found.
  
          :param str image_id: image identifier
          :return: str - api url of the image