Fatal error: Uncaught Error: Class "Drupal\image\Form\ImageStyleFormBase" not found in /home/www/drupal8/test/core/modules/image/src/Form/ImageStyleEditForm.php:18 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/image/src/Form/ImageStyleEditForm.php on line 18