code: def _get_image(self):
          
          if self.image is None:
              image_path = '%s/%s' % (current_app.static_folder, os.path.normpath(self.image_path))
              try:
                  self.image = Image.open(image_path)
                  self._reduce_opacity()
              except Exception as err:
                  raise ValueError('Unsupported watermark format: %s' % str(err))
  
          return self.image
docs: Prepare watermark image
          :return: Image.Image