diff --git a/include/functions_url.inc.php b/include/functions_url.inc.php
index 08fdbd5a9..34c3232aa 100644
--- a/include/functions_url.inc.php
+++ b/include/functions_url.inc.php
@@ -104,6 +104,11 @@ function add_url_params($url, $params, $arg_separator='&' )
 {
   if ( !empty($params) )
   {
+    if (defined('IN_WS') and '&' === $arg_separator)
+    {
+      $arg_separator = '&';
+    }
+
     assert( is_array($params) );
     $is_first = true;
     foreach($params as $param=>$val)
diff --git a/include/ws_functions.inc.php b/include/ws_functions.inc.php
index 816c3cbb3..312c1c848 100644
--- a/include/ws_functions.inc.php
+++ b/include/ws_functions.inc.php
@@ -169,7 +169,7 @@ function ws_std_get_urls($image_row)
   $ret['download_url'] = null;
   if ($provide_download_url)
   {
-    $ret['download_url'] = str_replace('&', '&', get_action_url($image_row['id'], 'e', true));
+    $ret['download_url'] = get_action_url($image_row['id'], 'e', true);
   }
 
   $derivatives = DerivativeImage::get_all($src_image);