diff --git a/app/models/post.rb b/app/models/post.rb
index e40ceb758..2ba462085 100644
--- a/app/models/post.rb
+++ b/app/models/post.rb
@@ -288,7 +288,7 @@ class Post < ActiveRecord::Base
       when %r{\Ahttp://img\d+\.pixiv\.net/img/[^\/]+/(\d+)}i, %r{\Ahttp://i\d\.pixiv\.net/img\d+/img/[^\/]+/(\d+)}i
         "http://www.pixiv.net/member_illust.php?mode=medium&illust_id=#{$1}"
 
-      when %r{\Ahttp://i\d\.pixiv\.net/img-original/img/(?:\d+\/)+(\d+)_p}, %r{\Ahttp://i\d\.pixiv\.net/c/\d+x\d+/img-master/img/(?:\d+\/)+(\d+)_p}
+      when %r{\Ahttp://i\d\.pixiv\.net/img-original/img/(?:\d+\/)+(\d+)_p}i, %r{\Ahttp://i\d\.pixiv\.net/c/\d+x\d+/img-master/img/(?:\d+\/)+(\d+)_p}i
         "http://www.pixiv.net/member_illust.php?mode=medium&illust_id=#{$1}"
 
       when %r{\Ahttp://lohas\.nicoseiga\.jp/priv/(\d+)\?e=\d+&h=[a-f0-9]+}i, %r{\Ahttp://lohas\.nicoseiga\.jp/priv/[a-f0-9]+/\d+/(\d+)}i