Wordpress Backend Tweaks: Control Admin Columns + Add Thumbnail FOR ALL POST TYPES [Archived]

gistfile1.txt

//POST ADMIN COLUMNS --->
add_filter('manage_posts_columns' , 'df_custom_columns');
function df_custom_columns( $columns ) {
    $columns = array(
        'cb' => '<input type="checkbox" />',
        'featured_image' => 'Image',
        'title' => 'Title',
        'categories' => 'Categories',
		    'tags'  => 'Tags',
        'date' => 'Date'
     );
    return $columns;
}

//**Post Admin Thumbnails
add_action( 'manage_posts_custom_column' , 'df_custom_columns_data', 10, 2 );
function df_custom_columns_data( $column, $post_id ) {
    switch ( $column ) {
    case 'featured_image':
        $thumb = get_the_post_thumbnail_url( $post_id, 'thumbnail' );
			echo ($thumb) ? '<img src="'.$thumb.'" width="150px" height="auto">' : '';
			break;
    }
}

// POST ADMIN COLUMNS <---