diff --git a/core/modules/editor/src/Form/EditorImageDialog.php b/core/modules/editor/src/Form/EditorImageDialog.php
index 0e148d22f1103b3de8fca8f615cfdd86d23c9c4b..0de74e5b0c0133ef5f4575ec58046764f78b2f58 100644
--- a/core/modules/editor/src/Form/EditorImageDialog.php
+++ b/core/modules/editor/src/Form/EditorImageDialog.php
@@ -141,7 +141,7 @@ public function buildForm(array $form, FormStateInterface $form_state, Editor $e
     }
     $form['attributes']['alt'] = [
       '#title' => $this->t('Alternative text'),
-      '#placeholder' => $this->t('Short description for the visually impaired'),
+      '#description' => $this->t('Short description of the image used by screen readers and displayed when the image is not loaded. This is important for accessibility.'),
       '#type' => 'textfield',
       '#required' => TRUE,
       '#required_error' => $this->t('Alternative text is required.<br />(Only in rare cases should this be left empty. To create empty alternative text, enter <code>""</code> — two double quotes without any content).'),
diff --git a/core/modules/image/src/Plugin/Field/FieldType/ImageItem.php b/core/modules/image/src/Plugin/Field/FieldType/ImageItem.php
index 67a15a7d008423503dc03f081baf2ce7459642eb..b3aa0c9fa7b2bd6f0fe8dedf308826a55b69c505 100644
--- a/core/modules/image/src/Plugin/Field/FieldType/ImageItem.php
+++ b/core/modules/image/src/Plugin/Field/FieldType/ImageItem.php
@@ -263,7 +263,7 @@ public function fieldSettingsForm(array $form, FormStateInterface $form_state) {
       '#type' => 'checkbox',
       '#title' => t('Enable <em>Alt</em> field'),
       '#default_value' => $settings['alt_field'],
-      '#description' => t('The alt attribute may be used by search engines, screen readers, and when the image cannot be loaded. Enabling this field is recommended.'),
+      '#description' => t('Short description of the image used by screen readers and displayed when the image is not loaded. Enabling this field is recommended.'),
       '#weight' => 9,
     ];
     $element['alt_field_required'] = [
@@ -433,7 +433,7 @@ protected function defaultImageForm(array &$element, array $settings) {
     $element['default_image']['alt'] = [
       '#type' => 'textfield',
       '#title' => t('Alternative text'),
-      '#description' => t('This text will be used by screen readers, search engines, and when the image cannot be loaded.'),
+      '#description' => t('Short description of the image used by screen readers and displayed when the image is not loaded. This is important for accessibility.'),
       '#default_value' => $settings['default_image']['alt'],
       '#maxlength' => 512,
     ];
diff --git a/core/modules/image/src/Plugin/Field/FieldWidget/ImageWidget.php b/core/modules/image/src/Plugin/Field/FieldWidget/ImageWidget.php
index 16160b25c6cdeb97fd60c91be220c7d08e7587be..d7556b4ed6a85e30555fd7e583e550094519d9ee 100644
--- a/core/modules/image/src/Plugin/Field/FieldWidget/ImageWidget.php
+++ b/core/modules/image/src/Plugin/Field/FieldWidget/ImageWidget.php
@@ -263,7 +263,7 @@ public static function process($element, FormStateInterface $form_state, $form)
       '#title' => t('Alternative text'),
       '#type' => 'textfield',
       '#default_value' => isset($item['alt']) ? $item['alt'] : '',
-      '#description' => t('This text will be used by screen readers, search engines, or when the image cannot be loaded.'),
+      '#description' => t('Short description of the image used by screen readers and displayed when the image is not loaded. This is important for accessibility.'),
       // @see https://www.drupal.org/node/465106#alt-text
       '#maxlength' => 512,
       '#weight' => -12,