diff --git a/app/models/alchemy/attachment/url.rb b/app/models/alchemy/attachment/url.rb
index 9a23e808b5..1a45204e5b 100644
--- a/app/models/alchemy/attachment/url.rb
+++ b/app/models/alchemy/attachment/url.rb
@@ -23,6 +23,7 @@ def initialize(attachment)
       # @return [String]
       #
       def call(options = {})
+        options[:format] ||= @attachment.suffix
         if options.delete(:download)
           routes.download_attachment_path(@attachment, options)
         else
diff --git a/spec/models/alchemy/attachment_spec.rb b/spec/models/alchemy/attachment_spec.rb
index 8ae673a7ba..f8df895354 100644
--- a/spec/models/alchemy/attachment_spec.rb
+++ b/spec/models/alchemy/attachment_spec.rb
@@ -63,14 +63,14 @@ module Alchemy
         let(:attachment) { create(:alchemy_attachment) }
 
         it "returns local path" do
-          is_expected.to eq "/attachment/#{attachment.id}/show"
+          is_expected.to eq "/attachment/#{attachment.id}/show.png"
         end
 
         context "with download enabled" do
           subject { attachment.url(download: true) }
 
           it "returns local download path" do
-            is_expected.to eq "/attachment/#{attachment.id}/download"
+            is_expected.to eq "/attachment/#{attachment.id}/download.png"
           end
 
           context "with extra params given" do
@@ -88,7 +88,7 @@ module Alchemy
           subject { attachment.url(download: false) }
 
           it "returns local path" do
-            is_expected.to eq "/attachment/#{attachment.id}/show"
+            is_expected.to eq "/attachment/#{attachment.id}/show.png"
           end
 
           context "with extra params given" do