diff --git a/lib/classes/AlterHtmlInit.php b/lib/classes/AlterHtmlInit.php
index 40d600e7..34cfc272 100644
--- a/lib/classes/AlterHtmlInit.php
+++ b/lib/classes/AlterHtmlInit.php
@@ -43,12 +43,12 @@ public static function alterHtml($content)
         }
 
         if (get_option('webp-express-alter-html-replacement') == 'picture') {
-            require_once __DIR__ . "../../../vendor/autoload.php";
+            require_once __DIR__ . "/../../vendor/autoload.php";
             require_once __DIR__ . '/AlterHtmlHelper.php';
             require_once __DIR__ . '/AlterHtmlPicture.php';
             return \WebPExpress\AlterHtmlPicture::replace($content);
         } else {
-            require_once __DIR__ . "../../../vendor/autoload.php";
+            require_once __DIR__ . "/../../vendor/autoload.php";
             require_once __DIR__ . '/AlterHtmlHelper.php';
             require_once __DIR__ . '/AlterHtmlImageUrls.php';
             return \WebPExpress\AlterHtmlImageUrls::replace($content);