title: Picturefill.js: Need help converting <picture> to the <img> srcset/sizes method
body: <p>This is what I have...</p>
  
  <pre><code>&lt;picture&gt;
      &lt;source srcset="assets/images/home/desktop-hero.jpg" media="(min-width: 768px)" /&gt;
      &lt;source srcset="assets/images/home/mobile-hero.jpg" media="(max-width: 767px)" /&gt;
      &lt;img class="hero-image-main ratio-content" src="assets/images/home/mobile-hero.jpg" /&gt;
  &lt;/picture&gt;
  </code></pre>