title: XamlParseException when trying to access Image from Resource directory
body: <p>Im using the following code to define a ImageBrush in a Window or UserControl:</p>
  
  <pre><code>&lt;ImageBrush x:Key="WindowBackground" Stretch="None" ImageSource="pack://application:,,,/Resources/bg1.tif"/&gt;
  </code></pre>
  
  <p>This works great, if I use it in my normal application.</p>
  
  <p>But for my testing project when I'm trying to instantiate this, I always get a XamlParseException for this line.</p>
  
  <p>Any hints how to avoid that?</p>
  
  <pre><code>   [TestMethod]
     public void TestMethod1()
     {
        MainWindow window = new MainWindow();
     }
  </code></pre>