code: def _plots_are_current(src_file, image_file):
      
  
      first_image_file = image_file.format(1)
      has_image = os.path.exists(first_image_file)
      src_file_changed = check_md5sum_change(src_file)
  
      return has_image and not src_file_changed
docs: Test existence of image file and no change in md5sum of
      example