diff -u b/core/modules/image/image.module b/core/modules/image/image.module
--- b/core/modules/image/image.module
+++ b/core/modules/image/image.module
@@ -423,7 +423,7 @@
   $fid = $entity->settings['default_image']['fid'];
   if ($fid) {
     $original_fid = isset($entity->original) ? $entity->original->settings['default_image']['fid'] : NULL;
-    if ($entity->settings['default_image']['fid'] != $original_fid) {
+    if ($fid != $original_fid) {
       $image = \Drupal::service('image.factory')->get(file_load($fid)->getFileUri());
       $entity->settings['default_image']['width'] = $image->getWidth();
       $entity->settings['default_image']['height'] = $image->getHeight();
diff -u b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php
--- b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php
+++ b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php
@@ -335,7 +335,7 @@
       '#description' => t('Image to be shown if no image is uploaded.'),
       '#default_value' => empty($settings['default_image']['fid']) ? array() : array($settings['default_image']['fid']),
       '#upload_location' => $settings['uri_scheme'] . '://default_images/',
-      '#element_validate' => array(array($this, 'validateDefaultImageForm')),
+      '#element_validate' => array('file_managed_file_validate', array(get_class($this), 'validateDefaultImageForm')),
     );
     $element['default_image']['alt'] = array(
       '#type' => 'textfield',
@@ -373,11 +373,7 @@
    * @param array $form_state
    *   The form state.
    */
-  public function validateDefaultImageForm(array &$element, array &$form_state) {
-    // Call the original validator to ensure referencing an existing file is
-    // only allowed if there are existing references.
-    file_managed_file_validate($element, $form_state);
-
+  public static function validateDefaultImageForm(array &$element, array &$form_state) {
     // Consolidate the array value of this field to a single FID as #extended
     // for default image is not TRUE and this is a single value.
     if (isset($element['fids']['#value'][0])) {