diff --git a/config/initializers/dragonfly.rb b/config/initializers/dragonfly.rb
index 786b23a6b5..3c4cd6aeb5 100644
--- a/config/initializers/dragonfly.rb
+++ b/config/initializers/dragonfly.rb
@@ -9,3 +9,6 @@
   ActiveRecord::Base.extend Dragonfly::Model
   ActiveRecord::Base.extend Dragonfly::Model::Validations
 end
+
+# Dragonfly 1.4.0 only allows `quality` as argument to `encode`
+Dragonfly::ImageMagick::Processors::Encode::WHITELISTED_ARGS << "flatten"