diff --git a/core/modules/responsive_image/src/ResponsiveImageStyleForm.php b/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
index 5e53c60..84b2123 100644
--- a/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
+++ b/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
@@ -115,6 +115,7 @@ public function form(array $form, FormStateInterface $form_state) {
         $label = $multiplier . ' ' . $breakpoint->getLabel() . ' [' . $breakpoint->getMediaQuery() . ']';
         $form['keyed_styles'][$breakpoint_id][$multiplier] = array(
           '#type' => 'container',
+          '#title' => $label,
         );
         $image_style_mapping = $responsive_image_style->getImageStyleMapping($breakpoint_id, $multiplier);
         $form['keyed_styles'][$breakpoint_id][$multiplier]['image_mapping_type'] = array(
@@ -127,9 +128,9 @@ public function form(array $form, FormStateInterface $form_state) {
           ),
           '#default_value' => isset($image_style_mapping['image_mapping_type']) ? $image_style_mapping['image_mapping_type'] : '_none',
         );
-        $form['keyed_styles'][$breakpoint_id][$multiplier]['image_style'] = array(
+        $form['keyed_styles'][$breakpoint_id][$multiplier]['image_mapping'] = array(
           '#type' => 'select',
-          '#title' => $label,
+          '#title' => $this->t('Image style'),
           '#options' => $image_styles,
           '#default_value' => isset($image_style_mapping['image_mapping']) ? $image_style_mapping['image_mapping'] : array(),
           '#description' => $this->t('Select an image style for this breakpoint.'),
@@ -139,7 +140,7 @@ public function form(array $form, FormStateInterface $form_state) {
             ),
           ),
         );
-        $form['keyed_styles'][$breakpoint_id][$multiplier]['sizes'] = array(
+        $form['keyed_styles'][$breakpoint_id][$multiplier]['image_mapping']['sizes'] = array(
           '#type' => 'textfield',
           '#title' => $this->t('Sizes'),
           '#default_value' => isset($image_style_mapping['image_mapping']['sizes']) ? $image_style_mapping['image_mapping']['sizes'] : '',
@@ -150,7 +151,7 @@ public function form(array $form, FormStateInterface $form_state) {
             ),
           ),
         );
-        $form['keyed_styles'][$breakpoint_id][$multiplier]['sizes_image_styles'] = array(
+        $form['keyed_styles'][$breakpoint_id][$multiplier]['image_mapping']['sizes_image_styles'] = array(
           '#title' => $this->t('Image styles'),
           '#type' => 'checkboxes',
           '#options' => array_diff_key($image_styles, array('' => '')),
diff --git a/core/modules/responsive_image/src/Tests/ResponsiveImageAdminUITest.php b/core/modules/responsive_image/src/Tests/ResponsiveImageAdminUITest.php
index 4c6c303..49dc5fa 100644
--- a/core/modules/responsive_image/src/Tests/ResponsiveImageAdminUITest.php
+++ b/core/modules/responsive_image/src/Tests/ResponsiveImageAdminUITest.php
@@ -81,12 +81,12 @@ public function testResponsiveImageAdmin() {
       // Check if the radio buttons are present.
       $this->assertFieldByName('keyed_styles[responsive_image_test_module.' . $case[0] . '][' . $case[1] . '][image_mapping_type]', '');
       // Check if the image style dropdowns are present.
-      $this->assertFieldByName('keyed_styles[responsive_image_test_module.' . $case[0] . '][' . $case[1] . '][image_style]', '');
+      $this->assertFieldByName('keyed_styles[responsive_image_test_module.' . $case[0] . '][' . $case[1] . '][image_mapping]', '');
       // Check if the sizes textfields are present.
-      $this->assertFieldByName('keyed_styles[responsive_image_test_module.' . $case[0] . '][' . $case[1] . '][sizes]', '');
+      $this->assertFieldByName('keyed_styles[responsive_image_test_module.' . $case[0] . '][' . $case[1] . '][image_mapping][sizes]', '');
       // Check if the image styles checkboxes are present.
       foreach (array_keys(image_style_options(FALSE)) as $image_style_name) {
-        $this->assertFieldByName('keyed_styles[responsive_image_test_module.' . $case[0] . '][' . $case[1] . '][sizes_image_styles][' . $image_style_name . ']');
+        $this->assertFieldByName('keyed_styles[responsive_image_test_module.' . $case[0] . '][' . $case[1] . '][image_mapping][sizes_image_styles][' . $image_style_name . ']');
       }
     }
 
@@ -96,37 +96,33 @@ public function testResponsiveImageAdmin() {
       'breakpoint_group' => 'responsive_image_test_module',
       'fallback_image_style' => 'thumbnail',
       'keyed_styles[responsive_image_test_module.mobile][1x][image_mapping_type]' => 'image_style',
-      'keyed_styles[responsive_image_test_module.mobile][1x][image_style]' => 'thumbnail',
+      'keyed_styles[responsive_image_test_module.mobile][1x][image_mapping]' => 'thumbnail',
       'keyed_styles[responsive_image_test_module.narrow][1x][image_mapping_type]' => 'sizes',
-      'keyed_styles[responsive_image_test_module.narrow][1x][sizes]' => '(min-width: 700px) 700px, 100vw',
-      'keyed_styles[responsive_image_test_module.narrow][1x][sizes_image_styles][large]' => 'large',
-      'keyed_styles[responsive_image_test_module.narrow][1x][sizes_image_styles][medium]' => 'medium',
+      'keyed_styles[responsive_image_test_module.narrow][1x][image_mapping][sizes]' => '(min-width: 700px) 700px, 100vw',
+      'keyed_styles[responsive_image_test_module.narrow][1x][image_mapping][sizes_image_styles][large]' => 'large',
+      'keyed_styles[responsive_image_test_module.narrow][1x][image_mapping][sizes_image_styles][medium]' => 'medium',
       'keyed_styles[responsive_image_test_module.wide][1x][image_mapping_type]' => 'image_style',
-      'keyed_styles[responsive_image_test_module.wide][1x][image_style]' => 'large',
+      'keyed_styles[responsive_image_test_module.wide][1x][image_mapping]' => 'large',
     );
     $this->drupalPostForm('admin/config/media/responsive-image-style/style_one', $edit, t('Save'));
     $this->drupalGet('admin/config/media/responsive-image-style/style_one');
 
     // Check the mapping for multipliers 1x and 2x for the mobile breakpoint.
-    $this->assertFieldByName('keyed_styles[responsive_image_test_module.mobile][1x][image_style]', 'thumbnail');
+    $this->assertFieldByName('keyed_styles[responsive_image_test_module.mobile][1x][image_mapping]', 'thumbnail');
     $this->assertFieldByName('keyed_styles[responsive_image_test_module.mobile][1x][image_mapping_type]', 'image_style');
-    $this->assertFieldByName('keyed_styles[responsive_image_test_module.mobile][2x][image_style]', '');
     $this->assertFieldByName('keyed_styles[responsive_image_test_module.mobile][2x][image_mapping_type]', '_none');
 
     // Check the mapping for multipliers 1x and 2x for the narrow breakpoint.
-    $this->assertFieldByName('keyed_mappings[responsive_image_test_module.narrow][1x][image_style]', '');
     $this->assertFieldByName('keyed_styles[responsive_image_test_module.narrow][1x][image_mapping_type]', 'sizes');
-    $this->assertFieldByName('keyed_styles[responsive_image_test_module.narrow][1x][sizes]', '(min-width: 700px) 700px, 100vw');
+    $this->assertFieldByName('keyed_styles[responsive_image_test_module.narrow][1x][image_mapping][sizes]', '(min-width: 700px) 700px, 100vw');
     $this->assertFieldChecked('edit-keyed_styles-responsive-image-test-modulenarrow-1x-sizes-image-styles-large');
     $this->assertFieldChecked('edit-keyed_styles-responsive-image-test-modulenarrow-1x-sizes-image-styles-medium');
     $this->assertNoFieldChecked('edit-keyed_styles-responsive-image-test-modulenarrow-1x-sizes-image-styles-thumbnail');
-    $this->assertFieldByName('keyed_styles[responsive_image_test_module.narrow][2x][image_style]', '');
     $this->assertFieldByName('keyed_styles[responsive_image_test_module.narrow][2x][image_mapping_type]', '_none');
 
     // Check the mapping for multipliers 1x and 2x for the wide breakpoint.
-    $this->assertFieldByName('keyed_styles[responsive_image_test_module.wide][1x][image_style]', 'large');
+    $this->assertFieldByName('keyed_styles[responsive_image_test_module.wide][1x][image_mapping]', 'large');
     $this->assertFieldByName('keyed_styles[responsive_image_test_module.wide][1x][image_mapping_type]', 'image_style');
-    $this->assertFieldByName('keyed_styles[responsive_image_test_module.wide][2x][image_style]', '');
     $this->assertFieldByName('keyed_styles[responsive_image_test_module.wide][2x][image_mapping_type]', '_none');
 
     // Delete the style.