Index: htmlmail.admin.inc
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/htmlmail/htmlmail.admin.inc,v
retrieving revision 1.2
diff -u -p -r1.2 htmlmail.admin.inc
--- htmlmail.admin.inc	15 Jul 2009 05:42:59 -0000	1.2
+++ htmlmail.admin.inc	15 Dec 2009 02:41:28 -0000
@@ -26,6 +26,13 @@ function htmlmail_admin_settings() {
     '#default_value' => variable_get('htmlmail_preformat', '1'),
     '#description' => t('Automagically inserts the &lt;HTML&gt; &lt;HEAD&gt; &lt;BODY&gt; tags, untick if you want control over this. Leave checked when using a WYSIWYG editor.<br /><em>Recommended when using template.</em>'),
   );
+  $form['htmlmail_rel_to_abs'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('Convert relative links to absolute'),
+    '#default_value' => variable_get('htmlmail_rel_to_abs', '0'),
+    '#description' => t('Automagically converts relative image links and URLs to absolute, untick if you want control over this.<br /><strong><a href="http://drupal.org/project/rel_to_abs">rel_to_abs</a></strong> needs to be installed and enabled.');
+    '#enabled' => (module_exists('rel_to_abs')) ? TRUE : FALSE,
+  );
   return system_settings_form($form);
 }
 
Index: htmlmail.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/htmlmail/htmlmail.module,v
retrieving revision 1.15
diff -u -p -r1.15 htmlmail.module
--- htmlmail.module	15 Jul 2009 05:42:59 -0000	1.15
+++ htmlmail.module	15 Dec 2009 02:41:28 -0000
@@ -82,6 +82,10 @@ function htmlmail_mail_alter(&$message) 
     $message['body'] = _filter_url($message['body'], 0);
   }
 
+  if (module_exists('rel_to_abs') && variable_get('htmlmail_rel_to_abs', '1') == 1) {
+    $message['body'] = rel_to_abs_filter('prepare', 0, -1, $message['body']);
+  }
+
   if (variable_get('htmlmail_emogrifier', '0') == 1) {
     $message['body'] = _htmlmail_emogrify($message);
   }