diff --git a/core/modules/image/image.module b/core/modules/image/image.module
index 12fa4fd..0d43de1 100644
--- a/core/modules/image/image.module
+++ b/core/modules/image/image.module
@@ -489,7 +489,7 @@ function image_field_config_delete(FieldConfigInterface $field) {
  * Implements hook_form_FORM_ID_alter().
  *
  * Alters the image dialog form for text editor, to allow the user to select an
- *   image style.
+ * image style.
  *
  * @see \Drupal\editor\Form\EditorImageDialog::buildForm()
  */
@@ -498,7 +498,7 @@ function image_form_editor_image_dialog_alter(&$form, FormStateInterface $form_s
   $editor = $form_state->getBuildInfo()['args'][0];
 
   // Alter the editor image dialog when image style functionality is available.
-  if ($editor->getFilterformat()->filters('filter_image_style')->status) {
+  if ($editor->getFilterFormat()->filters('filter_image_style')->status) {
     // Get the image (<img>) that is being edited on the client.
     $image_element = $form_state->getStorage()['image_element'];
 
@@ -506,14 +506,14 @@ function image_form_editor_image_dialog_alter(&$form, FormStateInterface $form_s
     $image_style_options = image_style_options(FALSE);
 
     // Add a select element to choose an image style.
-    $form['image_style']['selection'] = array(
+    $form['image_style']['selection'] = [
       '#title' => t('Image style'),
       '#type' => 'select',
       '#default_value' => isset($image_element['data-image-style']) ? $image_element['data-image-style'] : NULL,
       '#options' => $image_style_options,
       '#required' => TRUE,
-      '#parents' => array('attributes', 'data-image-style'),
-    );
+      '#parents' => ['attributes', 'data-image-style'],
+    ];
 
     $form['actions']['save_modal']['#validate'][] = 'image_form_editor_image_dialog_validate';
   }
@@ -552,10 +552,10 @@ function image_form_editor_image_dialog_validate(array &$form, FormStateInterfac
 
     if ($image->isValid()) {
       // Get the original width and height of the image.
-      $dimensions = array(
+      $dimensions = [
         'width' => $image->getWidth(),
         'height' => $image->getHeight(),
-      );
+      ];
 
       // Transform the 'width' and 'height' dimensions of the image based on the
       // image style.
diff --git a/core/modules/image/src/Plugin/CKEditorPlugin/DrupalImageStyle.php b/core/modules/image/src/Plugin/CKEditorPlugin/DrupalImageStyle.php
index d076508..98fbd1a 100644
--- a/core/modules/image/src/Plugin/CKEditorPlugin/DrupalImageStyle.php
+++ b/core/modules/image/src/Plugin/CKEditorPlugin/DrupalImageStyle.php
@@ -63,8 +63,8 @@ public function isEnabled(Editor $editor) {
     }
 
     // Automatically enable this plugin if the text format associated with this
-    // text editor uses the filter_image_style filter and the DrupalImage
-    // button is enabled.
+    // text editor uses the filter_image_style filter and the DrupalImage button
+    // is enabled.
     $format = $editor->getFilterFormat();
     if ($format->filters('filter_image_style')->status) {
       $toolbarButtons = CKEditorPluginManager::getEnabledButtons($editor);
diff --git a/core/modules/image/src/Plugin/Filter/FilterImageStyle.php b/core/modules/image/src/Plugin/Filter/FilterImageStyle.php
index 328daed..77a36b4 100644
--- a/core/modules/image/src/Plugin/Filter/FilterImageStyle.php
+++ b/core/modules/image/src/Plugin/Filter/FilterImageStyle.php
@@ -93,14 +93,14 @@ public static function create(ContainerInterface $container, array $configuratio
    */
   public function process($text, $langcode) {
     if (stristr($text, 'data-image-style') !== FALSE) {
-      // Load all image styles so each image found in the text can be
-      // checked against a valid image style.
+      // Load all image styles so each image found in the text can be checked
+      // against a valid image style.
       $image_styles = $this->loadImageStyles();
 
-      $dom = HTML::load($text);
+      $dom = Html::load($text);
       $xpath = new \DOMXPath($dom);
 
-      // Process each img element found with the necessary attributes.
+      // Process each image element found with the necessary attributes.
       /** @var \DOMElement $dom_element */
       foreach ($xpath->query('//*[@data-entity-type="file" and @data-entity-uuid and @data-image-style]') as $dom_element) {
         // Get the UUID and image style for the file.
@@ -108,7 +108,6 @@ public function process($text, $langcode) {
         $image_style_id = $dom_element->getAttribute('data-image-style');
 
         // If the image style is not a valid one, then don't transform the HTML.
-        // @TODO: File a follow-up. See #222-26.
         if (empty($file_uuid) || !in_array($image_style_id, $image_styles)) {
           continue;
         }
@@ -120,7 +119,7 @@ public function process($text, $langcode) {
         $dom_element->parentNode->replaceChild($altered_img, $dom_element);
       }
 
-      return new FilterProcessResult(HTML::serialize($dom));
+      return new FilterProcessResult(Html::serialize($dom));
     }
 
     // Process the filter if no image style img elements are found.
@@ -138,7 +137,7 @@ protected function loadImageStyles() {
   }
 
   /**
-   * Get the the width and height of an image based on the file UUID.
+   * Gets the the width and height of an image based on the file UUID.
    *
    * @param string $file_uuid
    *   The UUID for the file.
@@ -176,12 +175,6 @@ protected function getImageInfo($file_uuid) {
    *   The attributes array.
    */
   protected function prepareImageAttributes(\DOMElement $dom_element) {
-    // Remove attributes that are no longer needed.
-    // @TODO: File a follow-up. See #222-27.
-    $dom_element->removeAttribute('data-entity-type');
-    $dom_element->removeAttribute('data-entity-uuid');
-    $dom_element->removeAttribute('data-image-style');
-
     // Remove attributes that are generated by the image style.
     $dom_element->removeAttribute('width');
     $dom_element->removeAttribute('height');
@@ -198,7 +191,7 @@ protected function prepareImageAttributes(\DOMElement $dom_element) {
   }
 
   /**
-   * Get the HTML for the img element after image style is applied.
+   * Gets the HTML for the image element after image style is applied.
    *
    * @param string $file_uuid
    *   The UUID for the file.
diff --git a/core/modules/image/tests/src/Functional/FilterImageStyleTest.php b/core/modules/image/tests/src/Functional/FilterImageStyleTest.php
index 63528cb..2c403d6 100644
--- a/core/modules/image/tests/src/Functional/FilterImageStyleTest.php
+++ b/core/modules/image/tests/src/Functional/FilterImageStyleTest.php
@@ -8,6 +8,8 @@
 use Drupal\Core\Url;
 
 /**
+ * Tests FilterImageStyle conversion of inline images to utilize image styles.
+ *
  * @coversDefaultClass \Drupal\image\Plugin\Filter\FilterImageStyle
  * @group image
  */
@@ -20,9 +22,9 @@ class FilterImageStyleTest extends BrowserTestBase {
   public static $modules = ['filter', 'file', 'editor', 'node', 'image'];
 
   /**
-   * Text filter allowing images and has FilterImageStyle applied.
+   * A text format allowing images and with FilterImageStyle applied.
    *
-   * @var \Drupal\Core\Entity\EntityInterface
+   * @var \Drupal\Filter\FilterFormatInterface
    */
   protected $format;
 
@@ -37,13 +39,13 @@ protected function setUp() {
       'name' => $this->randomString(),
       'filters' => [
         'filter_html' => [
-          'status' => 1,
+          'status' => TRUE,
           'settings' => [
             'allowed_html' => '<img src alt data-entity-type data-entity-uuid data-align data-caption data-image-style width height>',
           ],
         ],
-        'filter_image_style' => ['status' => 1],
-        'editor_file_reference' => ['status' => 1],
+        'filter_image_style' => ['status' => TRUE],
+        'editor_file_reference' => ['status' => TRUE],
       ],
     ]);
     $this->format->save();
@@ -109,10 +111,6 @@ public function testImageStyle() {
     $image_element = $this->getSession()->getPage()->find('css', 'img.image-style-medium');
     $this->assertFalse(empty($image_element));
 
-    $this->assertFalse($image_element->hasAttribute('data-entity-type'));
-    $this->assertFalse($image_element->hasAttribute('data-entity-uuid'));
-    $this->assertFalse($image_element->hasAttribute('data-image-style'));
-
     $this->assertTrue(strpos($image_element->getAttribute('src'), 'medium'));
     $this->assertEquals('220', $image_element->getAttribute('width'));
     $this->assertEquals('164', $image_element->getAttribute('height'));
diff --git a/core/modules/image/tests/src/FunctionalJavascript/AddImageTest.php b/core/modules/image/tests/src/FunctionalJavascript/AddImageTest.php
index 2b33a5b..e4cc8f6 100644
--- a/core/modules/image/tests/src/FunctionalJavascript/AddImageTest.php
+++ b/core/modules/image/tests/src/FunctionalJavascript/AddImageTest.php
@@ -32,7 +32,7 @@ protected function setUp() {
       'format' => 'filtered_html',
       'name' => $this->randomString(),
       'filters' => [
-        'filter_image_style' => ['status' => 1],
+        'filter_image_style' => ['status' => TRUE],
       ],
     ]);
     $format->save();