diff --git a/include/user.inc.php b/include/user.inc.php
index 8bb62e76c..ded889409 100644
--- a/include/user.inc.php
+++ b/include/user.inc.php
@@ -102,10 +102,19 @@ if (
   and isset($_POST['password'])
 )
 {
-  if (!try_log_user($_POST['username'], $_POST['password'], false))
+  include_once(PHPWG_ROOT_PATH.'include/ws_init.inc.php');
+  include_once(PHPWG_ROOT_PATH.'include/ws_functions/pwg.php');
+
+  $credentials = array(
+    'username' => $_POST['username'],
+    'password' => $_POST['password']
+  );
+
+  $login = ws_session_login($credentials, $service);
+  
+  if (true !== $login)
   {
-    include_once(PHPWG_ROOT_PATH.'include/ws_init.inc.php');
-    $service->sendResponse(new PwgError(999, 'Invalid username/password'));
+    $service->sendResponse($login);
     exit();
   }
   $_SESSION['connected_with'] = 'pwg.images.uploadAsync';
diff --git a/ws.php b/ws.php
index a8628418b..ac86b4347 100644
--- a/ws.php
+++ b/ws.php
@@ -517,8 +517,8 @@ function ws_addDefaultMethods( $arr )
     'pwg.images.uploadAsync',
     'ws_images_uploadAsync',
     array(
-        'username' => array(),
-        'password' => array('default'=>null),
+        'username' => array('flags'=>WS_PARAM_OPTIONAL),
+        'password' => array('default'=>null, 'flags'=>WS_PARAM_OPTIONAL),
         'chunk' => array('type'=>WS_TYPE_INT|WS_TYPE_POSITIVE),
         'chunk_sum' => array(),
         'chunks' => array('type'=>WS_TYPE_INT|WS_TYPE_POSITIVE),
@@ -538,7 +538,7 @@ function ws_addDefaultMethods( $arr )
 <br>Start with chunk 0 (zero).
 <br>Set the form encoding to "form-data".
 <br>You can update an existing photo if you define an existing image_id.
-<br>Requires <b>admin</b> credentials.',
+<br>Requires <b>admin</b> credentials: either with username/password or header authorization with api key.',
       $ws_functions_root . 'pwg.images.php',
       array('admin_only'=>true, 'post_only'=>true)
     );