Image: Adding custom columns to the WordPress media library list is a great way to spot missing information. The same technique is easily applied to other WordPress Admin lists.

Searching through your WordPress media library for items without “alt” text, caption or description can be time consuming and is error prone, especially if you’ve more than a few images to check. A quick scan could easily reveal what information is missing; if only these three columns were available. Well, as you’ll see, it’s easy to add them with two minor additions to your WordPress theme’s functions.php file.

Define your custom columns

First we need to tell WordPress the internal and external names of the custom columns we want to add to the media library.

add_filter('manage_media_columns','isv_custom_media_column_headings');

function isv_custom_media_column_headings($defaults) {
   $defaults['isv_alt']     = 'Alt';
   $defaults['isv_caption'] = 'Caption';
   $defaults['isv_desc']    = 'Description';
   return $defaults;
}

You can enable and disable your custom columns using the screen options panel at the top of the page in exactly the same way as for the standard columns.

Fill your custom columns with data

For each media item WordPress asks us what value to show in each of our custom columns. The ALT text comes from a post metadata field, whereas the caption is stored in the post excerpt and the description in the post content.

add_action('manage_media_custom_column','isv_custom_media_column_content',10,2);

function isv_custom_media_column_content($column_name,$id) {
   $none = '<span style="background-color:yellow; color:black;">None</span>';
   switch ($column_name) {
      case 'isv_alt':
         $alt = get_post_meta($id,'_wp_attachment_image_alt',true);
         echo $alt ? $alt : $none;
         break;
      case 'isv_caption':
         $caption = get_the_excerpt();
         echo $caption ? $caption : $none;
         break;
      case 'isv_desc':
         $desc = get_the_content();
         echo $desc ? $desc : $none;
         break;
   }
}

I highlight “none” with an inline CSS style so missing information really stands out.

And that’s all there is to it. Simple!

Add custom columns to other WordPress Admin lists

Use the exact same approach to add custom columns to other WordPress Admin lists. Here are the filter and action names you’ll need:

Posts

Filter: manage_posts_columns, Action: manage_posts_custom_column

Pages

Filter: manage_pages_columns, Action: manage_pages_custom_column

Comments

Filter: manage_edit-comments_columns, Action: manage_comments_custom_column

I’ve added custom columns to my post and page lists for the excerpt and featured image thumbnail. On my comments list I’ve added a custom column to highlight pingbacks and trackbacks so they stand out amongst the other comments.

One of my hosting accounts limits PHP memory, so for these blogs I need to deactivate all plugins before running the automatic update. My other hosting service has enough PHP RAM to not have to do this, which is nice.

All my blogs have now been running WordPress 3.0 in production for a few days and so far I’ve not met any problems with the core product.

One minor issue has been with the CSS minification in the W3 Total Cache plugin. I’m using the latest development version of W3TC but it has an issue with CSS so I’ve disabled minification until I’ve time to look into this further.

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The Thesis theme I use on all my blogs is not multisite aware so I’d need to make some edits to the Thesis code to work in a multisite network.

So, I’ll leave my existing installations alone and give my core plugins and theme some time to catch up with WordPress core. Once they are multisite aware I’ll merge all my retired blogs into a single WordPress installation.

If you’re changing your WordPress site or blog structure and moving posts and pages around, then John Godley’s Redirection plugin makes it easy to add 301 redirects to the new canonical definitions. It also catches 404 errors, with an easy way to add redirects for incorrect URLs, common typos etc.