title: CSS background-image - What is the correct usage?
body: <p>What is the correct usage of the CSS background-image property?
  The key things I am trying to understand is</p>
  
  <ol>
  <li>Does it need to be in quotes i.e.: <code>background-image: url('images/slides/background.jpg');</code></li>
  <li>Can it be a relative path (as above) or must it be a full URL?</li>
  <li>Any other points I should be aware of to make sure it works correctly across standards compliant browsers.</li>
  </ol>