Picturefill

Markup

<picture>
    <!--[if IE 9]><video style="display: none;"><![endif]-->
    <source srcset="large.jpg,  large@2x.jpg  2x" media="(min-width: 80em)"><!--1280px-->
    <source srcset="medium.jpg, medium@2x.jpg 2x" media="(min-width: 40em)"><!-- 640px-->
    <!--[if IE 9]></video><![endif]-->
    <img srcset="small.jpg, small@2x.jpg 2x" alt="...">
</picture>
<noscript>
    <img src="small.jpg" alt="...">
</noscript>