Index: link.module
===================================================================
--- link.module	(revision 60)
+++ link.module	(working copy)
@@ -100,6 +100,13 @@
         '#maxlength' => 3,
         '#size' => 3,
       );
+
+      $form['extra_url_parameters'] = array(
+        '#type' => 'textfield',
+        '#title' => t('Extra URL parameters'),
+        '#default_value' => isset($field['extra_url_parameters']) ? $field['extra_url_parameters'] : '', 
+        '#description' => t('This field can be used to add additional text to the end of a url. Commonly used to enable thickbox usage.'),
+      );
       
       $target_options = array(
         'default' => t('Default (no target attribute)'),
@@ -137,13 +144,14 @@
       break;
 
     case 'save':
-      return array('attributes', 'display', 'title', 'title_value', 'enable_tokens');
+      return array('attributes', 'display', 'title', 'title_value', 'enable_tokens', 'extra_url_parameters');
 
     case 'database columns':
       return array(
         'url' => array('type' => 'varchar', 'length' => 255, 'not null' => TRUE, 'default' => "''"),
         'title' => array('type' => 'varchar', 'length' => 255, 'not null' => TRUE, 'default' => "''"),
         'attributes' => array('type' => 'mediumtext', 'not null' => FALSE),
+        'extra_url_parameters' => array('type' => 'varchar', 'length' => 255, 'not null' => TRUE, 'default' => "''"),
       );
 
     case 'filters':
@@ -597,6 +605,10 @@
     $url = substr($url, 0, strpos($url, '?'));
   }
   
+  if ($field['extra_url_parameters']) {
+    $query .= $field['extra_url_parameters'];
+  }
+  
   // Give the link the title 'Link'
   if ($formatter == 'short') {
     $output = l(t('Link'), $url, $attributes, $query, $fragment);
Index: link.install
===================================================================
--- link.install	(revision 60)
+++ link.install	(working copy)
@@ -43,3 +43,27 @@
   db_query('DELETE FROM {cache}');
   return $ret;
 }
+
+function link_update_2() {
+  $ret = array();
+
+  include_once(drupal_get_path('module', 'content') .'/content.module');
+  include_once(drupal_get_path('module', 'content') .'/content_admin.inc');
+
+  $fields = content_fields();
+  
+  foreach ($fields as $field) {
+    switch ($field['type']) {
+      case 'link':
+        $columns = array(
+          'extra_url_parameters' => array('type' => 'varchar', 'length' => 255, 'not null' => TRUE, 'default' => "''"),
+        );
+        
+        content_alter_db_field(array(), array(), $field, $columns);
+        $db_info = content_database_info($field);
+    }
+  }
+  
+  db_query('DELETE FROM {cache}');
+  return $ret;  
+}