diff --git a/actions/attachment_thumbnail.php b/actions/attachment_thumbnail.php
index c85029dcf6..e8f89ffc36 100644
--- a/actions/attachment_thumbnail.php
+++ b/actions/attachment_thumbnail.php
@@ -62,6 +62,6 @@ class Attachment_thumbnailAction extends AttachmentAction
             common_redirect($e->file->getUrl());
         }
 
-        common_redirect($thumbnail->getUrl());
+        common_redirect(File_thumbnail::url($thumbnail->filename));
     }
 }
diff --git a/classes/File_thumbnail.php b/classes/File_thumbnail.php
index 4c44e10fc1..1250f70404 100644
--- a/classes/File_thumbnail.php
+++ b/classes/File_thumbnail.php
@@ -142,7 +142,11 @@ class File_thumbnail extends Managed_DataObject
                 $this->url = null;
                 $this->update($orig);
             }
-            return self::url($this->filename);
+            $url = common_local_url('attachment_thumbnail', array('attachment'=>$this->file_id));
+            if (strpos($url, '?') === false) {
+                $url .= '?';
+            }
+            return $url . http_build_query(array('w'=>$this->width, 'h'=>$this->height));
         }
 
         // No local filename available, return the URL we have stored