protected function get_media_types() {
		$media_types = array();
		foreach ( get_allowed_mime_types() as $mime_type ) {
			$parts = explode( '/', $mime_type );
			if ( ! isset( $media_types[ $parts[0] ] ) ) {
				$media_types[ $parts[0] ] = array();
			}
			$media_types[ $parts[0] ][] = $mime_type;
		}
		return $media_types;
	}