diff --git a/core/modules/image/src/Normalizer/ImageItemNormalizer.php b/core/modules/image/src/Normalizer/ImageItemNormalizer.php
index 6bad572..d661a41 100644
--- a/core/modules/image/src/Normalizer/ImageItemNormalizer.php
+++ b/core/modules/image/src/Normalizer/ImageItemNormalizer.php
@@ -64,7 +64,13 @@ public function normalize($object, $format = NULL, array $context = array()) {
     $styles = ImageStyle::loadMultiple();
     $data['image_styles'] = [];
     foreach ($styles as $id => $style) {
-      $data['image_styles'][$id] = file_url_transform_relative($style->buildUrl($uri));
+      $dimensions = ['width' => $data['width'], 'height' => $data['height']];
+      $style->transformDimensions($dimensions, $uri);
+      $data['image_styles'][$id] = [
+        'url' => file_url_transform_relative($style->buildUrl($uri)),
+        'height' => empty($dimensions['height']) ? NULL : $dimensions['height'],
+        'width' => empty($dimensions['width']) ? NULL : $dimensions['width'],
+      ];
       $this->bubble($style);
     }
     return $data;
diff --git a/core/modules/image/tests/src/Kernel/Normalizer/ImageItemNormalizerTest.php b/core/modules/image/tests/src/Kernel/Normalizer/ImageItemNormalizerTest.php
index ee9fcf0..06f32f0 100644
--- a/core/modules/image/tests/src/Kernel/Normalizer/ImageItemNormalizerTest.php
+++ b/core/modules/image/tests/src/Kernel/Normalizer/ImageItemNormalizerTest.php
@@ -68,6 +68,17 @@ protected function setUp() {
       ],
     ])->save();
 
+    // Change all images style scale effect to upscale.
+    /** @var \Drupal\image\Entity\ImageStyle $image_style */
+    foreach (ImageStyle::loadMultiple() as $image_style) {
+      foreach ($image_style->getEffects() as $effect) {
+        $config = $effect->getConfiguration();
+        $config['data']['upscale'] = TRUE;
+        $effect->setConfiguration($config);
+      }
+      $image_style->save();
+    }
+
     file_unmanaged_copy(\Drupal::root() . '/core/misc/druplicon.png', 'public://example.jpg');
     $this->image = File::create([
       'uri' => 'public://example.jpg',
@@ -105,9 +116,24 @@ public function testNormalize() {
     $expected_image_style_keys = ['large', 'medium', 'thumbnail'];
     $this->assertEquals($cacheability, $context->pop());
     $this->assertEquals($expected_image_style_keys, $image_style_ids);
-
-    foreach ($data['image_test'][0]['image_styles'] as $id => $url) {
-      $this->assertNotEmpty(strstr($url, "files/styles/$id/public/example.jpg"));
+    $expect_dimensions = [
+      'large' => [
+        'width' => '422',
+        'height' => '480',
+      ],
+      'medium' => [
+        'width' => '194',
+        'height' => '220',
+      ],
+      'thumbnail' => [
+        'width' => '88',
+        'height' => '100',
+      ],
+    ];
+    foreach ($data['image_test'][0]['image_styles'] as $id => $img_info) {
+      $this->assertNotEmpty(strstr($img_info['url'], "files/styles/$id/public/example.jpg"));
+      $this->assertEquals($expect_dimensions[$id]['height'], $img_info['height'], "Style $id matches height.");
+      $this->assertEquals($expect_dimensions[$id]['width'], $img_info['width'], "Style $id matches width.");
     }
   }