public static function transform_image_fields( &$field ) {
		if ( empty( $field['value'] ) ) {
			return $field['value'];
		}

		foreach ( $field['sub_fields'] as $sub_field ) {
			if ( 'image' === $sub_field['type'] && 'id' === $sub_field['return_format'] ) {
				foreach ( $field['value'] as $id => $item ) {
					$field['value'][ $id ][ $sub_field['name'] ] =
						Image::get_image_fields( $field, $item[ $sub_field['name'] ], $sub_field['name'] );
				}
			}
		}
	}