A pull from http://coding.smashingmagazine.com/2013/06/02/clown-car-technique-solving-for-adaptive-images-in-responsive-web-design/

gistfile1.txt

<picture alt="responsive image"> 
     <source src="large.jpg" media="(min-width:1600px),
     (min-resolution: 136dpi) and (min-width:800px)">
     <source src="medium.jpg" media="(min-width:800px),
     (min-resolution: 136dpi) and (min-width:400px)">
     <source src="small.jpg">
  <!-- fallback -->
  <img src="small.jpg" alt="responsive image">
</picture>
/* via http://coding.smashingmagazine.com/2013/06/02/clown-car-technique-solving-for-adaptive-images-in-responsive-web-design/ */