diff --git a/app/models/spree/image.rb b/app/models/spree/image.rb
index 3ece2769aa..45d54a0880 100644
--- a/app/models/spree/image.rb
+++ b/app/models/spree/image.rb
@@ -6,8 +6,8 @@ module Spree
     validate :no_attachment_errors
 
     has_attached_file :attachment,
-                      styles: { mini: '48x48>', small: '100x100>',
-                                product: '240x240>', large: '600x600>' },
+                      styles: { mini: ["48x48#", :jpg], small: ["227x227#", :jpg],
+                                product: ["240x240>", :jpg], large: ["600x600>", :jpg] },
                       default_style: :product,
                       url: '/spree/products/:id/:style/:basename.:extension',
                       path: ':rails_root/public/spree/products/:id/:style/:basename.:extension',