diff --git a/app/assets/images/flags/cn.png b/app/assets/images/flags/cn.png
old mode 100755
new mode 100644
index 73e54843..c5ba1479
Binary files a/app/assets/images/flags/cn.png and b/app/assets/images/flags/cn.png differ
diff --git a/app/assets/images/flags/cn@2x.png b/app/assets/images/flags/cn@2x.png
new file mode 100644
index 00000000..609465d5
Binary files /dev/null and b/app/assets/images/flags/cn@2x.png differ
diff --git a/app/assets/images/flags/cn@4x.png b/app/assets/images/flags/cn@4x.png
new file mode 100644
index 00000000..17d9f8d6
Binary files /dev/null and b/app/assets/images/flags/cn@4x.png differ
diff --git a/app/assets/images/flags/de.png b/app/assets/images/flags/de.png
old mode 100755
new mode 100644
index 934428bd..b163fc60
Binary files a/app/assets/images/flags/de.png and b/app/assets/images/flags/de.png differ
diff --git a/app/assets/images/flags/de@2x.png b/app/assets/images/flags/de@2x.png
new file mode 100644
index 00000000..b96a1216
Binary files /dev/null and b/app/assets/images/flags/de@2x.png differ
diff --git a/app/assets/images/flags/de@4x.png b/app/assets/images/flags/de@4x.png
new file mode 100644
index 00000000..eeeb1406
Binary files /dev/null and b/app/assets/images/flags/de@4x.png differ
diff --git a/app/assets/images/flags/en.png b/app/assets/images/flags/en.png
index b1f517e1..47862532 100644
Binary files a/app/assets/images/flags/en.png and b/app/assets/images/flags/en.png differ
diff --git a/app/assets/images/flags/en@2x.png b/app/assets/images/flags/en@2x.png
new file mode 100644
index 00000000..689520a1
Binary files /dev/null and b/app/assets/images/flags/en@2x.png differ
diff --git a/app/assets/images/flags/en@4x.png b/app/assets/images/flags/en@4x.png
new file mode 100644
index 00000000..643f6ac0
Binary files /dev/null and b/app/assets/images/flags/en@4x.png differ
diff --git a/app/assets/images/flags/es.png b/app/assets/images/flags/es.png
index fb67bf4e..55ac7b43 100644
Binary files a/app/assets/images/flags/es.png and b/app/assets/images/flags/es.png differ
diff --git a/app/assets/images/flags/es@2x.png b/app/assets/images/flags/es@2x.png
new file mode 100644
index 00000000..e140e797
Binary files /dev/null and b/app/assets/images/flags/es@2x.png differ
diff --git a/app/assets/images/flags/es@4x.png b/app/assets/images/flags/es@4x.png
new file mode 100644
index 00000000..1d47fff1
Binary files /dev/null and b/app/assets/images/flags/es@4x.png differ
diff --git a/app/assets/images/flags/fr.png b/app/assets/images/flags/fr.png
index 3398f79d..0d05e487 100644
Binary files a/app/assets/images/flags/fr.png and b/app/assets/images/flags/fr.png differ
diff --git a/app/assets/images/flags/fr@2x.png b/app/assets/images/flags/fr@2x.png
new file mode 100644
index 00000000..b6e08502
Binary files /dev/null and b/app/assets/images/flags/fr@2x.png differ
diff --git a/app/assets/images/flags/fr@4x.png b/app/assets/images/flags/fr@4x.png
new file mode 100644
index 00000000..902e30d6
Binary files /dev/null and b/app/assets/images/flags/fr@4x.png differ
diff --git a/app/assets/images/flags/hk.png b/app/assets/images/flags/hk.png
old mode 100755
new mode 100644
index cb23585b..f6b532b4
Binary files a/app/assets/images/flags/hk.png and b/app/assets/images/flags/hk.png differ
diff --git a/app/assets/images/flags/hk@2x.png b/app/assets/images/flags/hk@2x.png
new file mode 100644
index 00000000..08d439ca
Binary files /dev/null and b/app/assets/images/flags/hk@2x.png differ
diff --git a/app/assets/images/flags/hk@4x.png b/app/assets/images/flags/hk@4x.png
new file mode 100644
index 00000000..1f909f5d
Binary files /dev/null and b/app/assets/images/flags/hk@4x.png differ
diff --git a/app/assets/images/flags/hr.png b/app/assets/images/flags/hr.png
old mode 100755
new mode 100644
index df73f6a9..351fbc11
Binary files a/app/assets/images/flags/hr.png and b/app/assets/images/flags/hr.png differ
diff --git a/app/assets/images/flags/hr@2x.png b/app/assets/images/flags/hr@2x.png
new file mode 100644
index 00000000..c5a0edc9
Binary files /dev/null and b/app/assets/images/flags/hr@2x.png differ
diff --git a/app/assets/images/flags/hr@4x.png b/app/assets/images/flags/hr@4x.png
new file mode 100644
index 00000000..045ab72c
Binary files /dev/null and b/app/assets/images/flags/hr@4x.png differ
diff --git a/app/assets/images/flags/id.png b/app/assets/images/flags/id.png
index c6bc0faf..acac8c33 100644
Binary files a/app/assets/images/flags/id.png and b/app/assets/images/flags/id.png differ
diff --git a/app/assets/images/flags/id@2x.png b/app/assets/images/flags/id@2x.png
new file mode 100644
index 00000000..ce68ec0b
Binary files /dev/null and b/app/assets/images/flags/id@2x.png differ
diff --git a/app/assets/images/flags/id@4x.png b/app/assets/images/flags/id@4x.png
new file mode 100644
index 00000000..cfeac32d
Binary files /dev/null and b/app/assets/images/flags/id@4x.png differ
diff --git a/app/assets/images/flags/ja.png b/app/assets/images/flags/ja.png
index 325fbad3..8030e1e1 100644
Binary files a/app/assets/images/flags/ja.png and b/app/assets/images/flags/ja.png differ
diff --git a/app/assets/images/flags/ja@2x.png b/app/assets/images/flags/ja@2x.png
new file mode 100644
index 00000000..61266f95
Binary files /dev/null and b/app/assets/images/flags/ja@2x.png differ
diff --git a/app/assets/images/flags/ja@4x.png b/app/assets/images/flags/ja@4x.png
new file mode 100644
index 00000000..ffb3be9f
Binary files /dev/null and b/app/assets/images/flags/ja@4x.png differ
diff --git a/app/assets/images/flags/ko.png b/app/assets/images/flags/ko.png
index 9c0a78eb..b1986cc5 100644
Binary files a/app/assets/images/flags/ko.png and b/app/assets/images/flags/ko.png differ
diff --git a/app/assets/images/flags/ko@2x.png b/app/assets/images/flags/ko@2x.png
new file mode 100644
index 00000000..688198a3
Binary files /dev/null and b/app/assets/images/flags/ko@2x.png differ
diff --git a/app/assets/images/flags/ko@4x.png b/app/assets/images/flags/ko@4x.png
new file mode 100644
index 00000000..4764c660
Binary files /dev/null and b/app/assets/images/flags/ko@4x.png differ
diff --git a/app/assets/images/flags/my.png b/app/assets/images/flags/my.png
index 9034cbab..c294cecf 100644
Binary files a/app/assets/images/flags/my.png and b/app/assets/images/flags/my.png differ
diff --git a/app/assets/images/flags/my@2x.png b/app/assets/images/flags/my@2x.png
new file mode 100644
index 00000000..21360234
Binary files /dev/null and b/app/assets/images/flags/my@2x.png differ
diff --git a/app/assets/images/flags/my@4x.png b/app/assets/images/flags/my@4x.png
new file mode 100644
index 00000000..0afabab5
Binary files /dev/null and b/app/assets/images/flags/my@4x.png differ
diff --git a/app/assets/images/flags/nl.png b/app/assets/images/flags/nl.png
old mode 100755
new mode 100644
index bd777974..b11e865d
Binary files a/app/assets/images/flags/nl.png and b/app/assets/images/flags/nl.png differ
diff --git a/app/assets/images/flags/nl@2x.png b/app/assets/images/flags/nl@2x.png
new file mode 100644
index 00000000..73b60cd9
Binary files /dev/null and b/app/assets/images/flags/nl@2x.png differ
diff --git a/app/assets/images/flags/nl@4x.png b/app/assets/images/flags/nl@4x.png
new file mode 100644
index 00000000..f2b9d111
Binary files /dev/null and b/app/assets/images/flags/nl@4x.png differ
diff --git a/app/assets/images/flags/pl.png b/app/assets/images/flags/pl.png
index 939f9d51..8cc138d5 100644
Binary files a/app/assets/images/flags/pl.png and b/app/assets/images/flags/pl.png differ
diff --git a/app/assets/images/flags/pl@2x.png b/app/assets/images/flags/pl@2x.png
new file mode 100644
index 00000000..d83bc654
Binary files /dev/null and b/app/assets/images/flags/pl@2x.png differ
diff --git a/app/assets/images/flags/pl@4x.png b/app/assets/images/flags/pl@4x.png
new file mode 100644
index 00000000..ee2efaca
Binary files /dev/null and b/app/assets/images/flags/pl@4x.png differ
diff --git a/app/assets/images/flags/pt.png b/app/assets/images/flags/pt.png
index 182c8c83..982db7b8 100644
Binary files a/app/assets/images/flags/pt.png and b/app/assets/images/flags/pt.png differ
diff --git a/app/assets/images/flags/pt@2x.png b/app/assets/images/flags/pt@2x.png
new file mode 100644
index 00000000..5ecfb2f3
Binary files /dev/null and b/app/assets/images/flags/pt@2x.png differ
diff --git a/app/assets/images/flags/pt@4x.png b/app/assets/images/flags/pt@4x.png
new file mode 100644
index 00000000..a66d5ee7
Binary files /dev/null and b/app/assets/images/flags/pt@4x.png differ
diff --git a/app/assets/images/flags/ro.png b/app/assets/images/flags/ro.png
index 37461b18..598e6f86 100644
Binary files a/app/assets/images/flags/ro.png and b/app/assets/images/flags/ro.png differ
diff --git a/app/assets/images/flags/ro@2x.png b/app/assets/images/flags/ro@2x.png
new file mode 100644
index 00000000..886bbf26
Binary files /dev/null and b/app/assets/images/flags/ro@2x.png differ
diff --git a/app/assets/images/flags/ro@4x.png b/app/assets/images/flags/ro@4x.png
new file mode 100644
index 00000000..ef477208
Binary files /dev/null and b/app/assets/images/flags/ro@4x.png differ
diff --git a/app/assets/images/flags/ru.png b/app/assets/images/flags/ru.png
old mode 100755
new mode 100644
index 723f7329..aae64f6e
Binary files a/app/assets/images/flags/ru.png and b/app/assets/images/flags/ru.png differ
diff --git a/app/assets/images/flags/ru@2x.png b/app/assets/images/flags/ru@2x.png
new file mode 100644
index 00000000..64f68ee1
Binary files /dev/null and b/app/assets/images/flags/ru@2x.png differ
diff --git a/app/assets/images/flags/ru@4x.png b/app/assets/images/flags/ru@4x.png
new file mode 100644
index 00000000..cd5b2bf6
Binary files /dev/null and b/app/assets/images/flags/ru@4x.png differ
diff --git a/app/assets/stylesheets/application.css b/app/assets/stylesheets/application.css
index fb30baeb..744e27f3 100644
--- a/app/assets/stylesheets/application.css
+++ b/app/assets/stylesheets/application.css
@@ -31,4 +31,6 @@
 
 .rjust { text-align: right ; }
 
-.qrcode { text-align: center; }
\ No newline at end of file
+.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
index 50788b9b..84393926 100644
--- 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'