diff --git a/core/java/android/app/Notification.java b/core/java/android/app/Notification.java
index 6e1d1cd2e4c9b..6bb35db6e712b 100644
--- a/core/java/android/app/Notification.java
+++ b/core/java/android/app/Notification.java
@@ -7917,6 +7917,8 @@ public class Notification implements Parcelable
          * @hide
          */
         public MessagingStyle setShortcutIcon(@Nullable Icon conversationIcon) {
+            // TODO(b/228941516): This icon should be downscaled to avoid using too much memory,
+            // see reduceImageSizes.
             mShortcutIcon = conversationIcon;
             return this;
         }
@@ -8423,6 +8425,51 @@ public class Notification implements Parcelable
             return makeMessagingView(StandardTemplateParams.VIEW_TYPE_HEADS_UP);
         }
 
+        /**
+         * @hide
+         */
+        @Override
+        public void reduceImageSizes(Context context) {
+            super.reduceImageSizes(context);
+            Resources resources = context.getResources();
+            boolean isLowRam = ActivityManager.isLowRamDeviceStatic();
+            if (mShortcutIcon != null) {
+                int maxSize = resources.getDimensionPixelSize(
+                        isLowRam ? R.dimen.notification_small_icon_size_low_ram
+                                : R.dimen.notification_small_icon_size);
+                mShortcutIcon.scaleDownIfNecessary(maxSize, maxSize);
+            }
+
+            int maxAvatarSize = resources.getDimensionPixelSize(
+                    isLowRam ? R.dimen.notification_person_icon_max_size
+                            : R.dimen.notification_person_icon_max_size_low_ram);
+            if (mUser != null && mUser.getIcon() != null) {
+                mUser.getIcon().scaleDownIfNecessary(maxAvatarSize, maxAvatarSize);
+            }
+
+            reduceMessagesIconSizes(mMessages, maxAvatarSize);
+            reduceMessagesIconSizes(mHistoricMessages, maxAvatarSize);
+        }
+
+        /**
+         * @hide
+         */
+        private static void reduceMessagesIconSizes(@Nullable List<Message> messages, int maxSize) {
+            if (messages == null) {
+                return;
+            }
+
+            for (Message message : messages) {
+                Person sender = message.mSender;
+                if (sender != null) {
+                    Icon icon = sender.getIcon();
+                    if (icon != null) {
+                        icon.scaleDownIfNecessary(maxSize, maxSize);
+                    }
+                }
+            }
+        }
+
         public static final class Message {
             /** @hide */
             public static final String KEY_TEXT = "text";
diff --git a/core/res/res/values/dimens.xml b/core/res/res/values/dimens.xml
index 323c72667c33b..5a6ee22756e98 100644
--- a/core/res/res/values/dimens.xml
+++ b/core/res/res/values/dimens.xml
@@ -779,6 +779,10 @@
     <dimen name="notification_left_icon_start">@dimen/notification_icon_circle_start</dimen>
     <!-- The alpha of a disabled notification button -->
     <item type="dimen" format="float" name="notification_action_disabled_alpha">0.5</item>
+    <!-- The maximum size of Person avatar image in MessagingStyle notifications.
+         This is bigger than displayed because listeners can use it for other displays
+         e.g. wearables. -->
+    <dimen name="notification_person_icon_max_size">144dp</dimen>
 
     <!-- The maximum size of the small notification icon on low memory devices. -->
     <dimen name="notification_small_icon_size_low_ram">@dimen/notification_small_icon_size</dimen>
@@ -792,6 +796,10 @@
     <dimen name="notification_big_picture_max_width_low_ram">294dp</dimen>
     <!-- The size of the right icon image when on low ram -->
     <dimen name="notification_right_icon_size_low_ram">@dimen/notification_right_icon_size</dimen>
+    <!-- The maximum size of Person avatar image in MessagingStyle notifications.
+     This is bigger than displayed because listeners can use it for other displays
+     e.g. wearables. -->
+    <dimen name="notification_person_icon_max_size_low_ram">96dp</dimen>
     <!-- The maximum size of the grayscale icon -->
     <dimen name="notification_grayscale_icon_max_size">256dp</dimen>
 
diff --git a/core/res/res/values/symbols.xml b/core/res/res/values/symbols.xml
index f177226c4ec33..0b13dde483110 100644
--- a/core/res/res/values/symbols.xml
+++ b/core/res/res/values/symbols.xml
@@ -3603,6 +3603,7 @@
   <java-symbol type="dimen" name="notification_actions_icon_drawable_size"/>
   <java-symbol type="dimen" name="notification_custom_view_max_image_height"/>
   <java-symbol type="dimen" name="notification_custom_view_max_image_width"/>
+  <java-symbol type="dimen" name="notification_person_icon_max_size" />
 
   <java-symbol type="dimen" name="notification_small_icon_size_low_ram"/>
   <java-symbol type="dimen" name="notification_big_picture_max_height_low_ram"/>
@@ -3611,6 +3612,7 @@
   <java-symbol type="dimen" name="notification_grayscale_icon_max_size"/>
   <java-symbol type="dimen" name="notification_custom_view_max_image_height_low_ram"/>
   <java-symbol type="dimen" name="notification_custom_view_max_image_width_low_ram"/>
+  <java-symbol type="dimen" name="notification_person_icon_max_size_low_ram" />
 
   <!-- Accessibility fingerprint gestures -->
   <java-symbol type="string" name="capability_title_canCaptureFingerprintGestures" />
diff --git a/core/tests/coretests/src/android/app/NotificationTest.java b/core/tests/coretests/src/android/app/NotificationTest.java
index e6d23643e8c03..a5da4424f7225 100644
--- a/core/tests/coretests/src/android/app/NotificationTest.java
+++ b/core/tests/coretests/src/android/app/NotificationTest.java
@@ -520,6 +520,70 @@ public class NotificationTest {
                         R.dimen.notification_small_icon_size));
     }
 
+    @Test
+    public void testBuild_ensureMessagingUserIsNotTooBig_resizesIcon() {
+        Icon hugeIcon = Icon.createWithBitmap(
+                Bitmap.createBitmap(3000, 3000, Bitmap.Config.ARGB_8888));
+        Icon hugeMessageAvatar = Icon.createWithBitmap(
+                Bitmap.createBitmap(3000, 3000, Bitmap.Config.ARGB_8888));
+        Icon hugeHistoricMessageAvatar = Icon.createWithBitmap(
+                Bitmap.createBitmap(3000, 3000, Bitmap.Config.ARGB_8888));
+
+        Notification.MessagingStyle style = new Notification.MessagingStyle(
+                new Person.Builder().setIcon(hugeIcon).setName("A User").build());
+        style.addMessage(new Notification.MessagingStyle.Message("A message", 123456,
+                new Person.Builder().setIcon(hugeMessageAvatar).setName("A Sender").build()));
+        style.addHistoricMessage(new Notification.MessagingStyle.Message("A message", 123456,
+                new Person.Builder().setIcon(hugeHistoricMessageAvatar).setName(
+                        "A Historic Sender").build()));
+        Notification notification = new Notification.Builder(mContext, "Channel").setStyle(
+                style).build();
+
+        Bitmap personIcon = style.getUser().getIcon().getBitmap();
+        assertThat(personIcon.getWidth()).isEqualTo(
+                mContext.getResources().getDimensionPixelSize(
+                        R.dimen.notification_person_icon_max_size));
+        assertThat(personIcon.getHeight()).isEqualTo(
+                mContext.getResources().getDimensionPixelSize(
+                        R.dimen.notification_person_icon_max_size));
+
+        Bitmap avatarIcon = style.getMessages().get(0).getSenderPerson().getIcon().getBitmap();
+        assertThat(avatarIcon.getWidth()).isEqualTo(
+                mContext.getResources().getDimensionPixelSize(
+                        R.dimen.notification_person_icon_max_size));
+        assertThat(avatarIcon.getHeight()).isEqualTo(
+                mContext.getResources().getDimensionPixelSize(
+                        R.dimen.notification_person_icon_max_size));
+
+        Bitmap historicAvatarIcon = style.getHistoricMessages().get(
+                0).getSenderPerson().getIcon().getBitmap();
+        assertThat(historicAvatarIcon.getWidth()).isEqualTo(
+                mContext.getResources().getDimensionPixelSize(
+                        R.dimen.notification_person_icon_max_size));
+        assertThat(historicAvatarIcon.getHeight()).isEqualTo(
+                mContext.getResources().getDimensionPixelSize(
+                        R.dimen.notification_person_icon_max_size));
+    }
+
+    @Test
+    public void testBuild_ensureMessagingShortcutIconIsNotTooBig_resizesIcon() {
+        Icon hugeIcon = Icon.createWithBitmap(
+                Bitmap.createBitmap(3000, 3000, Bitmap.Config.ARGB_8888));
+        Notification.MessagingStyle style = new Notification.MessagingStyle(
+                new Person.Builder().setName("A User").build()).setShortcutIcon(hugeIcon);
+
+        Notification notification = new Notification.Builder(mContext, "Channel").setStyle(
+                style).build();
+        Bitmap shortcutIcon = style.getShortcutIcon().getBitmap();
+
+        assertThat(shortcutIcon.getWidth()).isEqualTo(
+                mContext.getResources().getDimensionPixelSize(
+                        R.dimen.notification_small_icon_size));
+        assertThat(shortcutIcon.getHeight()).isEqualTo(
+                mContext.getResources().getDimensionPixelSize(
+                        R.dimen.notification_small_icon_size));
+    }
+
     @Test
     public void testColors_ensureColors_dayMode_producesValidPalette() {
         Notification.Colors c = new Notification.Colors();