title: Size an image to a percentage of html window
body: <p>Is it possible to define an image by a percentage of the document window? It's nested in several div tags, so it would be to somehow define its height% in reference to the window, rather than its parent tag. In effect, something like this...</p>
  
  <pre><code>&lt;img src="image.jpg"  height="50% of window"/&gt;
  </code></pre>