diff --git a/src/Plugin/ImageAPIOptimizeProcessor/GD.php b/src/Plugin/ImageAPIOptimizeProcessor/GD.php
index db12be1..d73bdea 100644
--- a/src/Plugin/ImageAPIOptimizeProcessor/GD.php
+++ b/src/Plugin/ImageAPIOptimizeProcessor/GD.php
@@ -35,7 +35,7 @@ class GD extends ConfigurableImageAPIOptimizeProcessorBase {
           // Convert stream wrapper URI to normal path.
           $destination = \Drupal::service('file_system')->realpath($image_uri);
           $success = $function($image->getToolkit()
-            ->getResource(), $destination, $this->configuration['quality']);
+            ->getImage(), $destination, $this->configuration['quality']);
         }
       }
     }