Responsive Image solutions

gistfile1.txt

#srcset - http://www.w3.org/html/wg/drafts/srcset/w3c-srcset/
<img alt="The Breakfast Combo"
         src="banner.jpeg"
         srcset="banner-HD.jpeg 2x, banner-phone.jpeg 100w, banner-phone-HD.jpeg 100w 2x">

#picture tag - http://picture.responsiveimages.org/
<picture id="pictureElement">
   <source media="(min-width: 45em)" srcset="large-1.jpg 1x, large-2.jpg 2x">
   <source media="(min-width: 18em)" srcset="med-1.jpg 1x, med-2.jpg 2x">
   <!-- assume media all --> 
   <source srcset="small-1.jpg 1x, small-2.jpg 2x">
   <!-- the following are ignored -->
   <source media=" is the message " srcset="">
</picture>

#Server side like sencha.io - http://www.sencha.com/learn/how-to-use-src-sencha-io/
<img
  src='http://src.sencha.io/x50r20/http://sencha.com/files/u.jpg'
  alt='Half the screen, rounded down to nearest 20 pixels'
/>