diff --git a/app/models/optimized_image.rb b/app/models/optimized_image.rb
index 5cdc0e1e63..4b3f219a54 100644
--- a/app/models/optimized_image.rb
+++ b/app/models/optimized_image.rb
@@ -118,7 +118,7 @@ class OptimizedImage < ActiveRecord::Base
     end
   end
 
-  IM_DECODERS ||= /\A(jpe?g|png|tiff?|bmp|ico)\z/i
+  IM_DECODERS ||= /\A(jpe?g|png|tiff?|bmp|ico|gif)\z/i
 
   def self.prepend_decoder!(path)
     extension = File.extname(path)[1..-1]