def get_image_output(self, arch):
        """
        Create the output for the image

        This is the Koji Content Generator metadata, along with the
        'docker save' output to upload.

        For metadata-only builds, an empty file is used instead of the
        output of 'docker save'.

        :param arch: str, architecture for this output
        :return: tuple, (metadata dict, Output instance)

        """

        saved_image = self.workflow.exported_image_sequence[-1].get('path')
        image_name = get_image_upload_filename(self.workflow.exported_image_sequence[-1],
                                               self.workflow.builder.image_id,
                                               arch)
        if self.metadata_only:
            metadata = self.get_output_metadata(os.path.devnull, image_name)
            output = Output(file=None, metadata=metadata)
        else:
            metadata = self.get_output_metadata(saved_image, image_name)
            output = Output(file=open(saved_image), metadata=metadata)

        return metadata, output