diff --git a/app/logical/storage_manager.rb b/app/logical/storage_manager.rb
index dcc2b044c..68d60dfa2 100644
--- a/app/logical/storage_manager.rb
+++ b/app/logical/storage_manager.rb
@@ -54,7 +54,7 @@ class StorageManager
     seo_tags = seo_tags(post) if tagged_filenames
 
     if type == :preview && !post.has_preview?
-      "#{base_url}/images/download-preview.png"
+      "#{root_url}/images/download-preview.png"
     elsif type == :preview
       "#{base_url}/preview/#{subdir}#{file}"
     elsif type == :large && post.has_large?
@@ -66,6 +66,12 @@ class StorageManager
 
   protected
 
+  def root_url
+    origin = Addressable::URI.parse(base_url).origin
+    origin = "" if origin == "null" # base_url was relative
+    origin
+  end
+
   def file_path(md5, file_ext, type)
     subdir = subdir_for(md5)
     file = file_name(md5, file_ext, type)
diff --git a/test/unit/storage_manager_test.rb b/test/unit/storage_manager_test.rb
index 5b4adc911..f440c2039 100644
--- a/test/unit/storage_manager_test.rb
+++ b/test/unit/storage_manager_test.rb
@@ -83,6 +83,16 @@ class StorageManagerTest < ActiveSupport::TestCase
         assert_equal("/data/sample/sample-#{@post.md5}.jpg", @storage_manager.file_url(@post, :large))
         assert_equal("/data/preview/#{@post.md5}.jpg", @storage_manager.file_url(@post, :preview))
       end
+
+      should "return the correct url for flash files" do
+        @post = FactoryGirl.create(:post, file_ext: "swf")
+
+        @storage_manager.stubs(:base_url).returns("/data")
+        assert_equal("/images/download-preview.png", @storage_manager.file_url(@post, :preview))
+
+        @storage_manager.stubs(:base_url).returns("http://localhost/data")
+        assert_equal("http://localhost/images/download-preview.png", @storage_manager.file_url(@post, :preview))
+      end
     end
   end