picture.html

<picture alt="fancy pants">
    <!-- loaded by browsers that support picture and that support one of the sources -->
    <source srcset="big.jpg 1x, big-2x.jpg 2x, big-3x.jpg" type="image/jpeg" media="(min-width: 40em)" />
    <source srcset="med.jpg 1x, med-2x.jpg 2x, big-3x.jpg" type="image/jpeg" />

    <!-- loaded by IE 8+, non-IE browsers that don’t support picture, and browsers that support picture but cannot find an appropriate source -->
    <![if gte IE 8]>
    <object data="fallback.jpg" type="image/jpeg"></object>
    <span class="fake-alt">fancy pants</span>
    <![endif]>

    <!-- loaded by IE 6 and 7 -->
    <!--[if lt IE 8]>
    <img src="fallback.jpg" alt="fancy pants" />
    <![endif]-->
</picture>