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
@@ -1037,11 +1037,14 @@
  * Transforms default image of image field from array into single value at save.
  */
 function image_entity_presave(Drupal\Core\Entity\EntityInterface $entity, $type) {
-  $instance = $type == 'field_instance';
-  $instance = $instance && config('field.field.' . $entity->field_name)->get('type') == 'image';
-  $field = $type == 'field_entity' && $entity->type == 'image';
-
-  if ($instance || $field) {
+  $field = FALSE;
+  if ($type == 'field_instance') {
+    $field = $entity->field;
+  }
+  if ($type == 'field_entity') {
+    $field = $entity;
+  }
+  if ($field && $field->type == 'image') {
     if (!empty($entity->settings['default_image'][0])) {
       $entity->settings['default_image'] = $entity->settings['default_image'][0];
     }