pic

pic.html

<picture>

  <!--[if IE 9]><video style="display: none;"><![endif]-->
  
  <source srcset="runner-wide.jpg" media="(min-width: 1000px)" />
  
  <source srcset="runner-narrow.jpg" media="(min-width: 600px)" />
  
  <!--[if IE 9]></video><![endif]-->
  
  <img srcset="runner-square.jpg" src="runner-wide.jpg" alt="Photograph of a man running along a pier at night, with a harbour in the background" />

</picture>

<!-- or using combining fallback src with the last set -->

<picture>

  <!--[if IE 9]><video style="display: none;"><![endif]-->
  
  <source srcset="runner-wide.jpg" media="(min-width: 1000px)" />
  
  <source srcset="runner-narrow.jpg" media="(min-width: 600px)" />
  
  <!--[if IE 9]></video><![endif]-->
  
  <img src="runner-square.jpg" alt="Photograph of a man running along a pier at night, with a harbour in the background" />

</picture>