diff --git a/core/modules/editor/src/Form/EditorImageDialog.php b/core/modules/editor/src/Form/EditorImageDialog.php
index dcacf64..b084022 100644
--- a/core/modules/editor/src/Form/EditorImageDialog.php
+++ b/core/modules/editor/src/Form/EditorImageDialog.php
@@ -90,8 +90,10 @@ public function buildForm(array $form, FormStateInterface $form_state, FilterFor
 
     // Construct strings to use in the upload validators.
     $image_upload = $editor->getImageUploadSettings();
-    if (!empty($image_upload['dimensions'])) {
-      $max_dimensions = $image_upload['dimensions']['max_width'] . '×' . $image_upload['dimensions']['max_height'];
+    if (!empty($image_upload['max_dimensions']['width']) && !empty($image_upload['max_dimensions']['height']) ) {
+      $max_width = (string) $image_upload['max_dimensions']['width'];
+      $max_height = (string) $image_upload['max_dimensions']['height'];
+      $max_dimensions = $max_width . 'x' . $max_height;
     }
     else {
       $max_dimensions = 0;