diff --git a/lib/chunks/engines.rb b/lib/chunks/engines.rb
index 4ed078d0..b6bb4a13 100644
--- a/lib/chunks/engines.rb
+++ b/lib/chunks/engines.rb
@@ -90,7 +90,7 @@ module Engines
                             :html_math_output_png => true,
                             :html_png_engine => 'blahtex',
                             :html_png_dir => @content.web.files_path.join('pngs').to_s,
-                            :html_png_url => '../files/pngs/',
+                            :html_png_url => @content.options[:png_url],
                             :content_only => true,
                             :author => @content.options[:engine_opts][:author],
                             :title => @content.options[:engine_opts][:title]})
@@ -104,7 +104,7 @@ module Engines
               :html_math_output_png => true,
               :html_png_engine => 'blahtex',
               :html_png_dir => @content.web.files_path.join('pngs').to_s,
-              :html_png_url => '../files/pngs/'}).to_html
+              :html_png_url => @content.options[:png_url]}).to_html
         html.gsub(/\A<div class="maruku_wrapper_div">\n?(.*?)\n?<\/div>\Z/m, '\1')
       end
     end
diff --git a/lib/url_generator.rb b/lib/url_generator.rb
index 9cb87930..efc3a501 100644
--- a/lib/url_generator.rb
+++ b/lib/url_generator.rb
@@ -7,6 +7,8 @@ class AbstractUrlGenerator
     @controller = controller
   end
 
+  attr :controller
+
   # Create a link for the given page (or file) name and link text based
   # on the render mode in options and whether the page (file) exists
   # in the web.
diff --git a/lib/wiki_content.rb b/lib/wiki_content.rb
index e047a96a..1dee5657 100644
--- a/lib/wiki_content.rb
+++ b/lib/wiki_content.rb
@@ -143,6 +143,12 @@ class WikiContent < String
     @options[:active_chunks] = (ACTIVE_CHUNKS - [WikiChunk::Word] ) if @web.brackets_only?
     @options[:hide_chunks] = (HIDE_CHUNKS - [Literal::Math] ) unless
                   [Engines::MarkdownMML, Engines::MarkdownPNG].include?(@options[:engine])
+    if @options[:engine] == Engines::MarkdownPNG
+      @options[:png_url] =
+         @options[:mode] == :export ? 'files/pngs/' :
+           (@url_generator.controller.url_for :controller => 'file', :web => @web.address, 
+           :action => 'file', :id => 'pngs', :only_path => true) + '/'
+    end
 
     @not_rendered = @pre_rendered = nil
 
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 6f005aa9..487fe4ee 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -104,9 +104,13 @@ end
 class StubUrlGenerator < AbstractUrlGenerator
 
   def initialize
-    super(:doesnt_need_controller)
+    controller = Object.new
+    def controller.url_for(options = {})
+        '../files/pngs'
+    end
+    super(controller)
   end
-
+  
   def file_link(mode, name, text, web_name, known_file, description)
     link = CGI.escape(name)
     case mode