diff --git a/app/assets/images/flags/cn.png b/app/assets/images/flags/cn.png
diff --git a/app/assets/images/flags/cn@2x.png b/app/assets/images/flags/cn@2x.png
diff --git a/app/assets/images/flags/cn@4x.png b/app/assets/images/flags/cn@4x.png
diff --git a/app/assets/images/flags/de.png b/app/assets/images/flags/de.png
diff --git a/app/assets/images/flags/de@2x.png b/app/assets/images/flags/de@2x.png
diff --git a/app/assets/images/flags/de@4x.png b/app/assets/images/flags/de@4x.png
diff --git a/app/assets/images/flags/en.png b/app/assets/images/flags/en.png
diff --git a/app/assets/images/flags/en@2x.png b/app/assets/images/flags/en@2x.png
diff --git a/app/assets/images/flags/en@4x.png b/app/assets/images/flags/en@4x.png
diff --git a/app/assets/images/flags/es.png b/app/assets/images/flags/es.png
diff --git a/app/assets/images/flags/es@2x.png b/app/assets/images/flags/es@2x.png
diff --git a/app/assets/images/flags/es@4x.png b/app/assets/images/flags/es@4x.png
diff --git a/app/assets/images/flags/fr.png b/app/assets/images/flags/fr.png
diff --git a/app/assets/images/flags/fr@2x.png b/app/assets/images/flags/fr@2x.png
diff --git a/app/assets/images/flags/fr@4x.png b/app/assets/images/flags/fr@4x.png
diff --git a/app/assets/images/flags/hk.png b/app/assets/images/flags/hk.png
diff --git a/app/assets/images/flags/hk@2x.png b/app/assets/images/flags/hk@2x.png
diff --git a/app/assets/images/flags/hk@4x.png b/app/assets/images/flags/hk@4x.png
diff --git a/app/assets/images/flags/hr.png b/app/assets/images/flags/hr.png
diff --git a/app/assets/images/flags/hr@2x.png b/app/assets/images/flags/hr@2x.png
diff --git a/app/assets/images/flags/hr@4x.png b/app/assets/images/flags/hr@4x.png
diff --git a/app/assets/images/flags/id.png b/app/assets/images/flags/id.png
diff --git a/app/assets/images/flags/id@2x.png b/app/assets/images/flags/id@2x.png
diff --git a/app/assets/images/flags/id@4x.png b/app/assets/images/flags/id@4x.png
diff --git a/app/assets/images/flags/ja.png b/app/assets/images/flags/ja.png
diff --git a/app/assets/images/flags/ja@2x.png b/app/assets/images/flags/ja@2x.png
diff --git a/app/assets/images/flags/ja@4x.png b/app/assets/images/flags/ja@4x.png
diff --git a/app/assets/images/flags/ko.png b/app/assets/images/flags/ko.png
diff --git a/app/assets/images/flags/ko@2x.png b/app/assets/images/flags/ko@2x.png
diff --git a/app/assets/images/flags/ko@4x.png b/app/assets/images/flags/ko@4x.png
diff --git a/app/assets/images/flags/my.png b/app/assets/images/flags/my.png
diff --git a/app/assets/images/flags/my@2x.png b/app/assets/images/flags/my@2x.png
diff --git a/app/assets/images/flags/my@4x.png b/app/assets/images/flags/my@4x.png
diff --git a/app/assets/images/flags/nl.png b/app/assets/images/flags/nl.png
diff --git a/app/assets/images/flags/nl@2x.png b/app/assets/images/flags/nl@2x.png
diff --git a/app/assets/images/flags/nl@4x.png b/app/assets/images/flags/nl@4x.png
diff --git a/app/assets/images/flags/pl.png b/app/assets/images/flags/pl.png
diff --git a/app/assets/images/flags/pl@2x.png b/app/assets/images/flags/pl@2x.png
diff --git a/app/assets/images/flags/pl@4x.png b/app/assets/images/flags/pl@4x.png
diff --git a/app/assets/images/flags/pt.png b/app/assets/images/flags/pt.png
diff --git a/app/assets/images/flags/pt@2x.png b/app/assets/images/flags/pt@2x.png
diff --git a/app/assets/images/flags/pt@4x.png b/app/assets/images/flags/pt@4x.png
diff --git a/app/assets/images/flags/ro.png b/app/assets/images/flags/ro.png
diff --git a/app/assets/images/flags/ro@2x.png b/app/assets/images/flags/ro@2x.png
diff --git a/app/assets/images/flags/ro@4x.png b/app/assets/images/flags/ro@4x.png
diff --git a/app/assets/images/flags/ru.png b/app/assets/images/flags/ru.png
diff --git a/app/assets/images/flags/ru@2x.png b/app/assets/images/flags/ru@2x.png
diff --git a/app/assets/images/flags/ru@4x.png b/app/assets/images/flags/ru@4x.png
diff --git a/app/assets/stylesheets/application.css b/app/assets/stylesheets/application.css
@@ -31,4 +31,6 @@
 
 .rjust { text-align: right ; }
 
-.qrcode { text-align: center; }
+.qrcode { text-align: center; }
+
+.flag { outline: 1px solid #ddd; }
diff --git a/app/views/layouts/application.html.haml b/app/views/layouts/application.html.haml
@@ -67,7 +67,8 @@
 
         %p.pull-right
           - ::Rails.application.config.available_locales.each do |locale|
-            = link_to image_tag("flags/#{locale}.png"), "?locale=#{locale}", data: {no_turbolink: true}
+            - flag_basename = "flags/#{locale}"
+            = link_to image_tag("#{flag_basename}.png", srcset: { "#{flag_basename}@2x.png" => "2x", "#{flag_basename}@4x.png" => "4x" }, class: "flag"), "?locale=#{locale}", data: {no_turbolink: true}
         %p
           ©
           = link_to t('tip4commit'), 'http://tip4commit.com/', target: '_blank'