diff --git a/app/logical/sources/strategies/base.rb b/app/logical/sources/strategies/base.rb
index bba04fb2c..1d357f5ee 100644
--- a/app/logical/sources/strategies/base.rb
+++ b/app/logical/sources/strategies/base.rb
@@ -70,7 +70,7 @@ module Sources
       end
 
       def referer_url(template)
-        template.params[:ref] || template.params[:url]
+        raise NotImplementedError
       end
 
       def image_urls
diff --git a/app/logical/sources/strategies/deviant_art.rb b/app/logical/sources/strategies/deviant_art.rb
index 63f9290a6..19306ea5b 100644
--- a/app/logical/sources/strategies/deviant_art.rb
+++ b/app/logical/sources/strategies/deviant_art.rb
@@ -6,7 +6,7 @@ module Sources
       end
 
       def referer_url(template)
-        if template.params[:ref] =~ /deviantart\.com\/art\//
+        if template.params[:ref] =~ /deviantart\.com\/art\// && template.params[:url] =~ /https?:\/\/(?:fc|th|pre|orig|img)\d{2}\.deviantart\.net\//
           template.params[:ref]
         else
           template.params[:url]
diff --git a/app/logical/sources/strategies/nico_seiga.rb b/app/logical/sources/strategies/nico_seiga.rb
index be83a9a4d..2ef00f579 100644
--- a/app/logical/sources/strategies/nico_seiga.rb
+++ b/app/logical/sources/strategies/nico_seiga.rb
@@ -6,7 +6,7 @@ module Sources
       end
 
       def referer_url(template)
-        if template.params[:ref] =~ /seiga\.nicovideo\.jp\/seiga\/im\d+/
+        if template.params[:ref] =~ /seiga\.nicovideo\.jp\/seiga\/im\d+/ && template.params[:url] =~ /http:\/\/lohas\.nicoseiga\.jp\/priv\//
           template.params[:ref]
         else
           template.params[:url]
diff --git a/app/logical/sources/strategies/nijie.rb b/app/logical/sources/strategies/nijie.rb
index 79cdbe1b9..1f5e7702e 100644
--- a/app/logical/sources/strategies/nijie.rb
+++ b/app/logical/sources/strategies/nijie.rb
@@ -6,7 +6,7 @@ module Sources
       end
 
       def referer_url(template)
-        if template.params[:ref] =~ /nijie\.info\/view\.php/ && template.params[:ref] =~ /id=\d+/
+        if template.params[:ref] =~ /nijie\.info\/view\.php.+id=\d+/ && template.params[:url] =~ /pic\d+\.nijie.info\/nijie_picture\//
           template.params[:ref]
         else
           template.params[:url]
diff --git a/app/logical/sources/strategies/pixiv.rb b/app/logical/sources/strategies/pixiv.rb
index d4e7044ad..3c333eb23 100644
--- a/app/logical/sources/strategies/pixiv.rb
+++ b/app/logical/sources/strategies/pixiv.rb
@@ -20,7 +20,7 @@ module Sources
       end
 
       def referer_url(template)
-        if template.params[:ref] =~ /pixiv\.net\/member_illust/ && template.params[:ref] =~ /mode=medium/
+        if template.params[:ref] =~ /pixiv\.net\/member_illust.+mode=medium/ && template.params[:url] =~ /#{IMG}|#{I12}/
           template.params[:ref]
         else
           template.params[:url]