POTUS Picturefill

<div data-picture data-alt="President Obama">
  <div data-srcset="small-1.jpg 1x, small-2.jpg 2x"></div>
  <div data-media="(min-width: 640px)"  data-srcset="med-1.jpg 1x, med-2.jpg 2x"></div>
  <div data-media="(min-width: 1280px)" data-srcset="large-1.jpg 1x, large-2.jpg 2x"></div>

  <!-- Fallback content for non-JS browsers. -->
  <noscript>
      <img src="med-1.jpg" alt="President Obama">
  </noscript>
</div>