wp_count_attachments()

wp_count_attachments( string|string[] $mime_type = '' ): stdClass

function wp_count_attachments( $mime_type = '' ) {
	global $wpdb;

	$cache_key = sprintf(
		'attachments%s',
		! empty( $mime_type ) ? ':' . str_replace( '/', '_', implode( '-', (array) $mime_type ) ) : ''
	);

	$counts = wp_cache_get( $cache_key, 'counts' );

	if ( false === $counts ) {
		$and   = wp_post_mime_type_where( $mime_type );
		$count = $wpdb->get_results( "SELECT post_mime_type, COUNT( * ) AS num_posts FROM $wpdb->posts WHERE post_type = 'attachment' AND post_status != 'trash' $and GROUP BY post_mime_type", ARRAY_A );

		$counts = array();
		foreach ( (array) $count as $row ) {
			$counts[ $row['post_mime_type'] ] = $row['num_posts'];
		}
		$counts['trash'] = $wpdb->get_var( "SELECT COUNT( * ) FROM $wpdb->posts WHERE post_type = 'attachment' AND post_status = 'trash' $and" );

		wp_cache_set( $cache_key, (object) $counts, 'counts' );
	}

	/**
	 * Filters the attachment counts by mime type.
	 *
	 * @since 3.7.0
	 *
	 * @param stdClass        $counts    An object containing the attachment counts by
	 *                                   mime type.
	 * @param string|string[] $mime_type Array or comma-separated list of MIME patterns.
	 */
	return apply_filters( 'wp_count_attachments', (object) $counts, $mime_type );
}