diff --git a/app/controllers/admin/custom_emojis_controller.rb b/app/controllers/admin/custom_emojis_controller.rb
index 00d069cdfb..37032e6ba4 100644
--- a/app/controllers/admin/custom_emojis_controller.rb
+++ b/app/controllers/admin/custom_emojis_controller.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'fastimage'
+
 module Admin
   class CustomEmojisController < BaseController
     def index
@@ -18,7 +20,11 @@ module Admin
     def create
       authorize :custom_emoji, :create?
 
+      image_size = FastImage.size(params[:custom_emoji][:image])
+
       @custom_emoji = CustomEmoji.new(resource_params)
+      @custom_emoji.image_width = image_size[0]
+      @custom_emoji.image_height = image_size[1]
 
       if @custom_emoji.save
         log_action :create, @custom_emoji
diff --git a/app/models/custom_emoji.rb b/app/models/custom_emoji.rb
index 0ebb28dc23..7e9eb91ca5 100644
--- a/app/models/custom_emoji.rb
+++ b/app/models/custom_emoji.rb
@@ -19,6 +19,8 @@
 #  visible_in_picker            :boolean          default(TRUE), not null
 #  category_id                  :bigint(8)
 #  image_storage_schema_version :integer
+#  image_width                  :integer
+#  image_height                 :integer
 #
 
 class CustomEmoji < ApplicationRecord
diff --git a/app/serializers/rest/custom_emoji_serializer.rb b/app/serializers/rest/custom_emoji_serializer.rb
index aff58e4d94..a4d2556849 100644
--- a/app/serializers/rest/custom_emoji_serializer.rb
+++ b/app/serializers/rest/custom_emoji_serializer.rb
@@ -3,7 +3,7 @@
 class REST::CustomEmojiSerializer < ActiveModel::Serializer
   include RoutingHelper
 
-  attributes :shortcode, :url, :static_url, :visible_in_picker
+  attributes :shortcode, :url, :static_url, :visible_in_picker, :width, :height
 
   attribute :category, if: :category_loaded?
 
@@ -22,4 +22,12 @@ class REST::CustomEmojiSerializer < ActiveModel::Serializer
   def category_loaded?
     object.association(:category).loaded? && object.category.present?
   end
+
+  def width
+    object.image_width
+  end
+
+  def height
+    object.image_height
+  end
 end
diff --git a/app/serializers/rest/emoji_reactions_grouped_by_name_serializer.rb b/app/serializers/rest/emoji_reactions_grouped_by_name_serializer.rb
index d4230de61a..48c70a4808 100644
--- a/app/serializers/rest/emoji_reactions_grouped_by_name_serializer.rb
+++ b/app/serializers/rest/emoji_reactions_grouped_by_name_serializer.rb
@@ -9,6 +9,8 @@ class REST::EmojiReactionsGroupedByNameSerializer < ActiveModel::Serializer
   attribute :url, if: :custom_emoji?
   attribute :static_url, if: :custom_emoji?
   attribute :domain, if: :custom_emoji?
+  attribute :width, if: :custom_emoji?
+  attribute :height, if: :custom_emoji?
   attribute :account_ids, if: :account_ids?
 
   def current_user?
@@ -34,4 +36,12 @@ class REST::EmojiReactionsGroupedByNameSerializer < ActiveModel::Serializer
   def domain
     object.custom_emoji.domain
   end
+
+  def width
+    object.custom_emoji.image_width
+  end
+
+  def height
+    object.custom_emoji.image_height
+  end
 end
diff --git a/db/migrate/20230308061833_add_image_size_to_custom_emojis.rb b/db/migrate/20230308061833_add_image_size_to_custom_emojis.rb
new file mode 100644
index 0000000000..ff048c6903
--- /dev/null
+++ b/db/migrate/20230308061833_add_image_size_to_custom_emojis.rb
@@ -0,0 +1,6 @@
+class AddImageSizeToCustomEmojis < ActiveRecord::Migration[6.1]
+  def change
+    add_column :custom_emojis, :image_width, :integer
+    add_column :custom_emojis, :image_height, :integer
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index cd085429f2..93a923bbe2 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2023_02_23_102416) do
+ActiveRecord::Schema.define(version: 2023_03_08_061833) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -338,6 +338,8 @@ ActiveRecord::Schema.define(version: 2023_02_23_102416) do
     t.boolean "visible_in_picker", default: true, null: false
     t.bigint "category_id"
     t.integer "image_storage_schema_version"
+    t.integer "image_width"
+    t.integer "image_height"
     t.index ["shortcode", "domain"], name: "index_custom_emojis_on_shortcode_and_domain", unique: true
   end