docs: def on_load_comparison(self, research=False):
          """
          Display the comparison image
          @param research: find a new comparison image even if one already known?
          """
  
          cutout = self.model.get_current_cutout()
          if research:
              cutout.comparison_image_index = None
          comparison_image = cutout.comparison_image
          if comparison_image is None:
              print "Failed to load comparison image: {}".format(cutout.comparison_image_list[cutout.comparison_image_index])
          else:
              self.view.display(cutout.comparison_image, self.use_pixel_coords)
              self.view.align(self.model.get_current_cutout(),
                              self.model.get_current_reading(),
                              self.model.get_current_source())
              self.model.get_current_workunit().previous_obs()
              self.model.acknowledge_image_displayed()