If you want to avoid this issue with a Drupal site, the file_public_base_url settings is helpful and you might -- or might not, given the latest comment there -

If you want to avoid this issue with a Drupal site, the file_public_base_url settings is helpful and you might -- or might not, given the latest comment there -- need the patch from this issue: https://www.drupal.org/node/2754273 https://www.drupal.org/node/2754273