code: def set_image(self, image, filename=None, resize=False):
          
          if self.id:
              data = self.connection.post('add_image', filename,
                  video_id=self.id, image=image.to_dict(), resize=resize)
              if data:
                  self.image = Image(data=data)
docs: Set the poster or thumbnail of a this Vidoe.