Usage of field_prefix and container-inline creates invalid markup.

In both editor_image_upload_settings_form() and Drupal\image\Plugin\Field\FieldType\ImageItem the field_prefix is set to a div with container-inline. This creates invalid markup similar to

<div id="edit-settings-max-resolution">
  <span class="field-prefix">
    <div class="container-inline">
      <div class="form-item-x">...</div>
      <div class="form-item-y">...</div>
      <span class="field-suffix"></div>
    </div>
  </span>
</div>