def columnSchema(self):
        """
        Returns the schema for the image column.

        :return: a :class:`StructType` for image column,
            ``struct<origin:string, height:int, width:int, nChannels:int, mode:int, data:binary>``.

        .. versionadded:: 2.4.0
        """

        if self._columnSchema is None:
            ctx = SparkContext._active_spark_context
            jschema = ctx._jvm.org.apache.spark.ml.image.ImageSchema.columnSchema()
            self._columnSchema = _parse_datatype_json_string(jschema.json())
        return self._columnSchema