diff --git a/OpenGraph.php b/OpenGraph.php
index af2e7b6..b9096f6 100644
--- a/OpenGraph.php
+++ b/OpenGraph.php
@@ -126,7 +126,7 @@ static private function _parse($HTML) {
         }
 
         //Fallback to use image_src if ogp::image isn't set.
-        if (!isset($page->values['image'])) {
+        if (!isset($page->_values['image'])) {
             $domxpath = new DOMXPath($doc);
             $elements = $domxpath->query("//link[@rel='image_src']");