Index: modules/file/file.field.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/file/file.field.inc,v
retrieving revision 1.10
diff -u -p -r1.10 file.field.inc
--- modules/file/file.field.inc	11 Nov 2009 08:32:35 -0000	1.10
+++ modules/file/file.field.inc	28 Nov 2009 17:26:45 -0000
@@ -253,6 +253,14 @@ function file_field_insert($obj_type, $o
  * Implement hook_field_update().
  */
 function file_field_update($obj_type, $object, $field, $instance, $langcode, &$items) {
+
+  // Set permanent status on files.
+  foreach ($items as $delta => $item) {
+    $file = file_load($item['fid']);
+    $file->status = $item['status'] = 1;
+    file_save($file);
+  }
+  
   // Check for files that have been removed from the object.
 
   // On new revisions, old files are always maintained in the previous revision.