diff --git a/core/modules/system/src/Tests/Update/FilterHtmlUpdateTest.php b/core/modules/system/src/Tests/Update/FilterHtmlUpdateTest.php
index 4e30452..51b2062 100644
--- a/core/modules/system/src/Tests/Update/FilterHtmlUpdateTest.php
+++ b/core/modules/system/src/Tests/Update/FilterHtmlUpdateTest.php
@@ -44,7 +44,7 @@ public function testAllowedHtmlUpdate() {
 
     // Make sure we have the expected values after the update.
     $filters_after = [
-      'basic_html' => '<a href hreflang> <em> <strong> <cite> <blockquote cite> <code> <ul type> <ol start type> <li> <dl> <dt> <dd> <h4 id> <h5 id> <h6 id> <p> <br> <span> <img src alt height width>',
+      'basic_html' => '<a href hreflang> <em> <strong> <cite> <blockquote cite> <code> <ul type> <ol start type> <li> <dl> <dt> <dd> <h4 id> <h5 id> <h6 id> <p> <br> <span> <img src alt height width data-align data-caption>',
       'restricted_html' => '<a href hreflang> <em> <strong> <cite> <blockquote cite> <code> <ul type> <ol start type> <li> <dl> <dt> <dd> <h4 id> <h5 id> <h6 id>',
     ];
     foreach ($filters_after as $name => $after) {
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index 39777f0..edfb5cd 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -1645,7 +1645,7 @@ function system_update_8007() {
  * Add allowed attributes to existing html filters.
  */
 function system_update_8008() {
-  $allowed_attribute_mapping = [
+  $default_mapping = [
     '<a>' => '<a href hreflang>',
     '<blockquote>' => '<blockquote cite>',
     '<ol>' => '<ol start type>',
@@ -1659,10 +1659,29 @@ function system_update_8008() {
   ];
   $config_factory = \Drupal::configFactory();
   foreach ($config_factory->listAll('filter.format') as $name) {
+    $allowed_html_mapping = $default_mapping;
     $config = $config_factory->getEditable($name);
+    // The image alignment filter needs the data-align attribute.
+    $align_enabled = $config->get('filters.filter_align.status');
+    if ($align_enabled) {
+      $allowed_html_mapping['<img>'] = str_replace('>', ' data-align>', $allowed_html_mapping['<img>']);
+    }
+    // The image caption filter needs the data-caption attribute.
+    $caption_enabled = $config->get('filters.filter_caption.status');
+    if ($caption_enabled) {
+      $allowed_html_mapping['<img>'] = str_replace('>', ' data-caption>', $allowed_html_mapping['<img>']);
+    }
     $allowed_html = $config->get('filters.filter_html.settings.allowed_html');
+    $align = $config->get('filters.filter_align.status');
+    if ($align) {
+      $allowed_attribute_mapping['<img>'] = str_replace('>', ' data-align>', $allowed_attribute_mapping['<img>']);
+    }
+    $caption = $config->get('filters.filter_caption.status');
+    if ($caption) {
+      $allowed_attribute_mapping['<img>'] = str_replace('>', ' data-caption>', $allowed_attribute_mapping['<img>']);
+    }
     if (!empty($allowed_html)) {
-      $allowed_html = strtr($allowed_html, $allowed_attribute_mapping);
+      $allowed_html = strtr($allowed_html, $allowed_html_mapping);
       $config->set('filters.filter_html.settings.allowed_html', $allowed_html);
       $config->save();
     }