code: def save(self, path, key, format, data):
          
          thumbpath = self.get_thumbpath(path, key, format)
          fullpath = os.path.join(self.out_path, thumbpath)
          self.save_thumb(fullpath, data)
          url = self.get_url(thumbpath)
          thumb = Thumb(url, key, fullpath)
          return thumb
docs: Save a newly generated thumbnail.
  
          path:
              path of the source image
          key:
              key of the thumbnail
          format:
              thumbnail's file extension
          data:
              thumbnail's binary data