title: 'Graying Out' a WPF button image?
body: <p>I have a simple <code>Button</code> control that contains an <code>Image</code> object as its content. I want so set the <code>Image</code> opacity to 0.5 when the <code>Button</code> is disabled to provide an additional visual cue as to the <code>Button</code> status. </p>
  
  <p>What is the simplest way to accomplish that result in XAML? Thanks for your help.</p>