私がどのように知っている唯一の方法は、独自の列の配列を作成することです
// Add to admin_init function
add_filter('manage_edit-au-gallery_columns', 'add_my_gallery_columns');
function add_my_gallery_columns($gallery_columns) {
        $new_columns['cb'] = '<input type="checkbox" />';
        $new_columns['id'] = __('ID');
        $new_columns['title'] = _x('Gallery Name', 'column name');
                // your new column somewhere good in the middle
        $new_columns['thumbnail'] = __('Thumbnail');
        $new_columns['categories'] = __('Categories');
        $new_columns['tags'] = __('Tags');
        $new_columns['date'] = _x('Date', 'column name');
        return $new_columns;
    }
そして、この追加された列を通常のようにレンダリングします
// Add to admin_init function
    add_action('manage_au-gallery_posts_custom_column', 'manage_gallery_columns', 10, 2);
    function manage_gallery_columns($column_name, $id) {
        global $wpdb;
        switch ($column_name) {
        case 'id':
            echo $id;
                break;
        case 'Thumbnail':
            $thumbnail_id = get_post_meta( $id, '_thumbnail_id', true );
                // image from gallery
                $attachments = get_children( array('post_parent' => $post_id, 'post_type' => 'attachment', 'post_mime_type' => 'image') );
                if ($thumbnail_id)
                    $thumb = wp_get_attachment_image( $thumbnail_id, array($width, $height), true );
                elseif ($attachments) {
                    foreach ( $attachments as $attachment_id => $attachment ) {
                        $thumb = wp_get_attachment_image( $attachment_id, array($width, $height), true );
                    }
                }
                if ( isset($thumb) && $thumb ) {echo $thumb; } else {echo __('None');}
            break;
        default:
            break;
        } // end switch
}
お役に立てれば