Adding this snippet to the functions.php of your WordPress theme will add the featured thumbnail to the post listing within the WordPress admin. This is a featured I added to my theme so that when creating posts I could more easily see what posts I had added thumbnails to.

add_filter('manage_posts_columns', 'posts_columns', 5); add_action('manage_posts_custom_column', 'posts_custom_columns', 5, 2); function posts_columns($defaults){ $defaults['admin_post_thumbs'] = __('Thumbs'); return $defaults; } function posts_custom_columns($column_name, $id){ if($column_name === 'admin_post_thumbs'){ echo the_post_thumbnail( 'featured-thumbnail' ); } }