get_post_thumbnail_id( int|WP_Post $post = null ): int|false

53function get_post_thumbnail_id( $post = null ) {54	$post = get_post( $post );55 56	if ( ! $post ) {57		return false;58	}59 60	$thumbnail_id = (int) get_post_meta( $post->ID, '_thumbnail_id', true );61 62	/**63	 * Filters the post thumbnail ID.64	 *65	 * @since 5.9.066	 *67	 * @param int|false        $thumbnail_id Post thumbnail ID or false if the post does not exist.68	 * @param int|WP_Post|null $post         Post ID or WP_Post object. Default is global `$post`.69	 */70	return (int) apply_filters( 'post_thumbnail_id', $thumbnail_id, $post );71}