diff --git a/core/modules/editor/src/Form/EditorImageDialog.php b/core/modules/editor/src/Form/EditorImageDialog.php
index 0e148d22f1..e0d3ee0ca8 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('This text will be used by screen readers, search engines, or when the image cannot be loaded.'),
       '#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).'),