Колонки с миниатюрами в админке

Featured image

//Get Featured image
add_filter( 'manage_posts_columns', 'mts_columns_head' );
add_action( 'manage_posts_custom_column', 'mts_columns_content', 10, 2 );
function mts_get_featured_image( $post_ID ) {
	$post_thumbnail_id = get_post_thumbnail_id( $post_ID );
	if ( $post_thumbnail_id ) {
		$post_thumbnail_img = wp_get_attachment_image_src( $post_thumbnail_id, 'thumbnail' );
		
		return $post_thumbnail_img[0];
	}
}

function mts_columns_head( $defaults ) {
	$defaults['featured_image'] = 'Миниатюра';
	
	return $defaults;
}

function mts_columns_content( $column_name, $post_ID ) {
	if ( $column_name == 'featured_image' ) {
		$post_featured_image = mts_get_featured_image( $post_ID );
		if ( $post_featured_image ) {
			echo '<img width="100" src="' . $post_featured_image . '" />';
		}
	}
}