_wp_preview_post_thumbnail_filter( null|array|string $value, int $post_id, string $meta_key ): null|array

957function _wp_preview_post_thumbnail_filter( $value, $post_id, $meta_key ) {958	$post = get_post();959 960	if ( ! $post ) {961		return $value;962	}963 964	if ( empty( $_REQUEST['_thumbnail_id'] ) || empty( $_REQUEST['preview_id'] )965		|| $post->ID !== $post_id || $post_id !== (int) $_REQUEST['preview_id']966		|| '_thumbnail_id' !== $meta_key || 'revision' === $post->post_type967	) {968		return $value;969	}970 971	$thumbnail_id = (int) $_REQUEST['_thumbnail_id'];972 973	if ( $thumbnail_id <= 0 ) {974		return '';975	}976 977	return (string) $thumbnail_id;978}