diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index d7387a2..ef2587a 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -2268,7 +2268,7 @@ function drupal_common_theme() {
       // - http://dev.w3.org/html5/spec/Overview.html#alt
       // The title attribute is optional in all cases, so it is omitted by
       // default.
-      'variables' => array('uri' => NULL, 'width' => NULL, 'height' => NULL, 'alt' => '', 'title' => NULL, 'attributes' => array(), 'sizes' => NULL),
+      'variables' => array('uri' => NULL, 'width' => NULL, 'height' => NULL, 'alt' => '', 'title' => NULL, 'style_name' => NULL, 'attributes' => array(), 'sizes' => NULL),
       'template' => 'image',
     ),
     'breadcrumb' => array(
diff --git a/core/modules/image/image.module b/core/modules/image/image.module
index 913fb7f..b2116e4 100644
--- a/core/modules/image/image.module
+++ b/core/modules/image/image.module
@@ -281,15 +281,13 @@ function template_preprocess_image_style(&$variables) {
 
   $style->transformDimensions($dimensions);
 
-  // Add in the image style name as an HTML class.
-  $variables['attributes']['class'][] = 'image-style-' . drupal_html_class($variables['style_name']);
-
   $variables['image'] = array(
     '#theme' => 'image',
     '#width' => $dimensions['width'],
     '#height' => $dimensions['height'],
     '#attributes' => $variables['attributes'],
     '#uri' => $style->buildUrl($variables['uri']),
+    '#style_name' => drupal_html_class($variables['style_name']),
   );
 
   if (isset($variables['alt']) || array_key_exists('alt', $variables)) {
diff --git a/core/modules/image/src/Tests/ImageDimensionsTest.php b/core/modules/image/src/Tests/ImageDimensionsTest.php
index 3d787d9..4d6c76b 100644
--- a/core/modules/image/src/Tests/ImageDimensionsTest.php
+++ b/core/modules/image/src/Tests/ImageDimensionsTest.php
@@ -67,7 +67,7 @@ function testImageDimensions() {
 
     $style->addImageEffect($effect);
     $style->save();
-    $this->assertEqual($this->getImageTag($variables), '<img class="image-style-test" src="' . $url . '" width="120" height="60" alt="" />');
+    $this->assertEqual($this->getImageTag($variables), '<img src="' . $url . '" width="120" height="60" alt="" class="image-style-test" />');
     $this->assertFalse(file_exists($generated_uri), 'Generated file does not exist.');
     $this->drupalGet($url);
     $this->assertResponse(200, 'Image was generated at the URL.');
@@ -88,7 +88,7 @@ function testImageDimensions() {
 
     $style->addImageEffect($effect);
     $style->save();
-    $this->assertEqual($this->getImageTag($variables), '<img class="image-style-test" src="' . $url . '" width="60" height="120" alt="" />');
+    $this->assertEqual($this->getImageTag($variables), '<img src="' . $url . '" width="60" height="120" alt="" class="image-style-test" />');
     $this->assertFalse(file_exists($generated_uri), 'Generated file does not exist.');
     $this->drupalGet($url);
     $this->assertResponse(200, 'Image was generated at the URL.');
@@ -110,7 +110,7 @@ function testImageDimensions() {
 
     $style->addImageEffect($effect);
     $style->save();
-    $this->assertEqual($this->getImageTag($variables), '<img class="image-style-test" src="' . $url . '" width="45" height="90" alt="" />');
+    $this->assertEqual($this->getImageTag($variables), '<img src="' . $url . '" width="45" height="90" alt="" class="image-style-test" />');
     $this->assertFalse(file_exists($generated_uri), 'Generated file does not exist.');
     $this->drupalGet($url);
     $this->assertResponse(200, 'Image was generated at the URL.');
@@ -132,7 +132,7 @@ function testImageDimensions() {
 
     $style->addImageEffect($effect);
     $style->save();
-    $this->assertEqual($this->getImageTag($variables), '<img class="image-style-test" src="' . $url . '" width="45" height="90" alt="" />');
+    $this->assertEqual($this->getImageTag($variables), '<img src="' . $url . '" width="45" height="90" alt="" class="image-style-test" />');
     $this->assertFalse(file_exists($generated_uri), 'Generated file does not exist.');
     $this->drupalGet($url);
     $this->assertResponse(200, 'Image was generated at the URL.');
@@ -150,7 +150,7 @@ function testImageDimensions() {
 
     $style->addImageEffect($effect);
     $style->save();
-    $this->assertEqual($this->getImageTag($variables), '<img class="image-style-test" src="' . $url . '" width="45" height="90" alt="" />');
+    $this->assertEqual($this->getImageTag($variables), '<img src="' . $url . '" width="45" height="90" alt="" class="image-style-test" />');
     $this->assertFalse(file_exists($generated_uri), 'Generated file does not exist.');
     $this->drupalGet($url);
     $this->assertResponse(200, 'Image was generated at the URL.');
@@ -171,7 +171,7 @@ function testImageDimensions() {
 
     $style->addImageEffect($effect);
     $style->save();
-    $this->assertEqual($this->getImageTag($variables), '<img class="image-style-test" src="' . $url . '" alt="" />');
+    $this->assertEqual($this->getImageTag($variables), '<img src="' . $url . '" alt="" class="image-style-test" />');
     $this->assertFalse(file_exists($generated_uri), 'Generated file does not exist.');
     $this->drupalGet($url);
     $this->assertResponse(200, 'Image was generated at the URL.');
@@ -191,7 +191,7 @@ function testImageDimensions() {
 
     $style->addImageEffect($effect);
     $style->save();
-    $this->assertEqual($this->getImageTag($variables), '<img class="image-style-test" src="' . $url . '" width="30" height="30" alt="" />');
+    $this->assertEqual($this->getImageTag($variables), '<img src="' . $url . '" width="30" height="30" alt="" class="image-style-test" />');
     $this->assertFalse(file_exists($generated_uri), 'Generated file does not exist.');
     $this->drupalGet($url);
     $this->assertResponse(200, 'Image was generated at the URL.');
@@ -212,7 +212,7 @@ function testImageDimensions() {
 
     $effect_id = $style->addImageEffect($effect);
     $style->save();
-    $this->assertEqual($this->getImageTag($variables), '<img class="image-style-test" src="' . $url . '" alt="" />');
+    $this->assertEqual($this->getImageTag($variables), '<img src="' . $url . '" alt="" class="image-style-test" />');
     $this->assertFalse(file_exists($generated_uri), 'Generated file does not exist.');
     $this->drupalGet($url);
     $this->assertResponse(200, 'Image was generated at the URL.');
@@ -231,7 +231,7 @@ function testImageDimensions() {
 
     $style->addImageEffect($effect);
     $style->save();
-    $this->assertEqual($this->getImageTag($variables), '<img class="image-style-test" src="' . $url . '" alt="" />');
+    $this->assertEqual($this->getImageTag($variables), '<img src="' . $url . '" alt="" class="image-style-test" />');
   }
 
   /**
diff --git a/core/modules/system/templates/image.html.twig b/core/modules/system/templates/image.html.twig
index b6b238a..97039e1 100644
--- a/core/modules/system/templates/image.html.twig
+++ b/core/modules/system/templates/image.html.twig
@@ -5,10 +5,16 @@
  *
  * Available variables:
  * - attributes: HTML attributes for the img tag.
+ * - style_name: (optional) The name of the image style applied.
  *
  * @see template_preprocess_image()
  *
  * @ingroup themeable
  */
 #}
-<img{{ attributes }} />
+{%
+set classes = [
+  style_name ? 'image-style-' ~ style_name,
+]
+%}
+<img{{ attributes.addClass(classes) }} />