diff --git a/app/serializers/rest/custom_emoji_serializer.rb b/app/serializers/rest/custom_emoji_serializer.rb
index 33da69da5..2d4706864 100644
--- a/app/serializers/rest/custom_emoji_serializer.rb
+++ b/app/serializers/rest/custom_emoji_serializer.rb
@@ -3,11 +3,11 @@
 class REST::CustomEmojiSerializer < ActiveModel::Serializer
   include RoutingHelper
 
-  # Please update `app/javascript/mastodon/api_types/custom_emoji.ts` when making changes to the attributes
-
   attributes :shortcode, :url, :static_url, :visible_in_picker
 
   attribute :category, if: :category_loaded?
+  attribute :width, if: :width?
+  attribute :height, if: :height?
 
   def url
     full_asset_url(object.image.url)
@@ -24,4 +24,20 @@ class REST::CustomEmojiSerializer < ActiveModel::Serializer
   def category_loaded?
     object.association(:category).loaded? && object.category.present?
   end
+
+  def width?
+    object.respond_to?(:image_width) || object.respond_to?(:width)
+  end
+
+  def height?
+    object.respond_to?(:image_height) || object.respond_to?(:height)
+  end
+
+  def width
+    object.respond_to?(:image_width) ? object.image_width : object.width
+  end
+
+  def height
+    object.respond_to?(:image_height) ? object.image_height : object.height
+  end
 end