--- a/upload_replace.module	Tue Nov 22 12:50:02 2016
+++ b/upload_replace.module	Fri Jun 24 22:20:42 2016
@@ -31,7 +31,7 @@
     return;
   }
 
-  $desired_destination = preg_replace('/_[0-9]+\.(.*)$/', '.$1', $new_file->uri);
+  $desired_destination = preg_replace('/_[0-9]+\.([^\.]*)$/', '.$1', $new_file->uri);
 
   $db_path = db_select('file_managed', 'f')
     ->fields('f', array('uri'))