title: Resize an image in HTML/CSS for mobile devices
body: <p>I have a background image and I really can't figure out how to resize it for mobile devices... I've tried everything! Width: 100%, max-width: 100%; etc.
  Is it the height/cover thats affecting it?</p>
  
  <pre><code>.jumbotron {
    background-image:url('http://www.part-box.com/images/yellow-frog.png');
    height: 500px;
    background-repeat: no-repeat;
    background-size: cover;
  }
  </code></pre>