title: Featured Image column of admin for custom post types not working
body: <p>I have added code to my <code>function.php</code> file to add the Featured Image of a post to my admin column. It works great for posts and pages, but for my two custom post types (cars, wheels) it doesn't do anything to the admin layout.</p>
  
  <p>Can someone help me with this? Do I need to add a filter for each custom?</p>
  
  <p>I got this code from here: <a href="http://www.tcbarrett.com/2011/10/add-featured-image-thumbnail-to-wordpress-admin-columns/" rel="nofollow">Add featured image thumbnail to WordPress admin columns</a></p>
  
  <p>The following code in my <code>function.php</code> file:</p>
  
  <pre><code>// Add the posts and pages columns filter. They can both use the same function.
  add_filter('manage_posts_columns', 'tcb_add_post_thumbnail_column', 5);
  add_filter('manage_pages_columns', 'tcb_add_post_thumbnail_column', 5);
  add_filter('manage_custom_post_columns', 'tcb_add_post_thumbnail_column', 5);
  
  // Add the column
  function tcb_add_post_thumbnail_column($cols){
    $cols['tcb_post_thumb'] = __('FeaTured');
    return $cols;
  }
  
  // Hook into the posts an pages column managing. Sharing function callback again.
  add_action('manage_posts_custom_column', 'tcb_display_post_thumbnail_column', 5, 2);
  add_action('manage_pages_custom_column', 'tcb_display_post_thumbnail_column', 5, 2);
      add_action('manage_custom_post_column', 'tcb_display_post_thumbnail_column', 5, 2);
  
  // Grab featured-thumbnail size post thumbnail and display it.
  function tcb_display_post_thumbnail_column($col, $id){
    switch($col){
      case 'tcb_post_thumb':
        if( function_exists('the_post_thumbnail') )
          echo the_post_thumbnail( 'admin-list-thumb' );
        else
          echo 'Not supported in theme';
        break;
    }
  }
  </code></pre>