diff --git a/app/logical/sources/strategies/nico_seiga.rb b/app/logical/sources/strategies/nico_seiga.rb
index b19200a4b..d35b1a8e7 100644
--- a/app/logical/sources/strategies/nico_seiga.rb
+++ b/app/logical/sources/strategies/nico_seiga.rb
@@ -65,33 +65,25 @@ module Sources
       end
 
       def image_urls
-        urls = []
-        return urls if api_client&.api_response.blank?
-
         if image_id.present?
-          urls << "https://seiga.nicovideo.jp/image/source/#{image_id}"
+          [image_url_for("https://seiga.nicovideo.jp/image/source/#{image_id}")]
         elsif illust_id.present?
-          urls << "https://seiga.nicovideo.jp/image/source/#{illust_id}"
+          [image_url_for("https://seiga.nicovideo.jp/image/source/#{illust_id}")]
         elsif manga_id.present? && api_client.image_ids.present?
-          urls += api_client.image_ids.map { |id| "https://seiga.nicovideo.jp/image/source/#{id}" }
+          api_client.image_ids.map { |id| image_url_for("https://seiga.nicovideo.jp/image/source/#{id}") }
+        else
+          [image_url_for(url)]
         end
-        urls
       end
 
-      def image_url
-        return url if image_urls.blank? || api_client.blank?
+      def image_url_for(url)
+        return url if api_client.blank?
 
-        img = case url
-        when DIRECT || CDN_DIRECT then "https://seiga.nicovideo.jp/image/source/#{image_id_from_url(url)}"
-        when SOURCE then url
-        else image_urls.first
-        end
-
-        resp = api_client.login.head(img)
+        resp = api_client.login.head(url)
         if resp.uri.to_s =~ %r{https?://.+/(\w+/\d+/\d+)\z}i
           "https://lohas.nicoseiga.jp/priv/#{$1}"
         else
-          img
+          url
         end
       end
 
diff --git a/test/unit/sources/nico_seiga_test.rb b/test/unit/sources/nico_seiga_test.rb
index 303b14b2b..11bd81a8c 100644
--- a/test/unit/sources/nico_seiga_test.rb
+++ b/test/unit/sources/nico_seiga_test.rb
@@ -37,19 +37,20 @@ module Sources
         assert_match(%r{^https?://lohas\.nicoseiga\.jp/priv/}, @site_1.image_url)
         assert_match(%r{^https?://lohas\.nicoseiga\.jp/priv/}, @site_2.image_url)
 
-        expected = %w[
-          https://seiga.nicovideo.jp/image/source/10315315
-          https://seiga.nicovideo.jp/image/source/10315318
-          https://seiga.nicovideo.jp/image/source/10315319
-          https://seiga.nicovideo.jp/image/source/10315320
-          https://seiga.nicovideo.jp/image/source/10315321
-          https://seiga.nicovideo.jp/image/source/10315322
-          https://seiga.nicovideo.jp/image/source/10315323
-          https://seiga.nicovideo.jp/image/source/10315324
-          https://seiga.nicovideo.jp/image/source/10315316
+        expected = [
+          %r{https://lohas\.nicoseiga\.jp/priv/\h+/\d+/10315315},
+          %r{https://lohas\.nicoseiga\.jp/priv/\h+/\d+/10315318},
+          %r{https://lohas\.nicoseiga\.jp/priv/\h+/\d+/10315319},
+          %r{https://lohas\.nicoseiga\.jp/priv/\h+/\d+/10315320},
+          %r{https://lohas\.nicoseiga\.jp/priv/\h+/\d+/10315321},
+          %r{https://lohas\.nicoseiga\.jp/priv/\h+/\d+/10315322},
+          %r{https://lohas\.nicoseiga\.jp/priv/\h+/\d+/10315323},
+          %r{https://lohas\.nicoseiga\.jp/priv/\h+/\d+/10315324},
+          %r{https://lohas\.nicoseiga\.jp/priv/\h+/\d+/10315316},
         ]
-        assert_equal(expected.sort, @site_3.image_urls.sort)
-        assert_match(%r{^https?://lohas\.nicoseiga\.jp/priv/}, @site_3.image_url)
+
+        assert_equal(9, @site_3.image_urls.size)
+        9.times { |n| assert_match(expected[n], @site_3.image_urls[n]) }
       end
 
       should "get the canonical url" do