docs: def from_file(cls, image_descriptor):
          """
          Return a new |Image| subclass instance loaded from the image file
          identified by *image_descriptor*, a path or file-like object.
          """
          if is_string(image_descriptor):
              path = image_descriptor
              with open(path, 'rb') as f:
                  blob = f.read()
                  stream = BytesIO(blob)
              filename = os.path.basename(path)
          else:
              stream = image_descriptor
              stream.seek(0)
              blob = stream.read()
              filename = None
          return cls._from_stream(stream, blob, filename)