diff --git a/app/models/custom_emoji.rb b/app/models/custom_emoji.rb
index e73cd9bd2753e0d037afccbcc000d8e7a3ab1000..def1b3faa162057c89a80601ac45df7f5a3ae9c1 100644
--- a/app/models/custom_emoji.rb
+++ b/app/models/custom_emoji.rb
@@ -27,13 +27,15 @@ class CustomEmoji < ApplicationRecord
     :(#{SHORTCODE_RE_FRAGMENT}):
     (?=[^[:alnum:]:]|$)/x
 
+  IMAGE_MIME_TYPES = %w(image/png image/gif image/webp).freeze
+
   has_one :local_counterpart, -> { where(domain: nil) }, class_name: 'CustomEmoji', primary_key: :shortcode, foreign_key: :shortcode
 
   has_attached_file :image, styles: { static: { format: 'png', convert_options: '-coalesce -strip' } }
 
   before_validation :downcase_domain
 
-  validates_attachment :image, content_type: { content_type: 'image/png' }, presence: true, size: { less_than: LIMIT }
+  validates_attachment :image, content_type: { content_type: IMAGE_MIME_TYPES }, presence: true, size: { less_than: LIMIT }
   validates :shortcode, uniqueness: { scope: :domain }, format: { with: /\A#{SHORTCODE_RE_FRAGMENT}\z/ }, length: { minimum: 2 }
 
   scope :local,      -> { where(domain: nil) }