<picture> <source srcset="examples/images/extralarge.jpg" media="(min-width: 1000px)"> <source srcset="examples/images/large.jpg" media="(min-width: 800px)"> <source srcset="examples/images/medium.jpg"> <img srcset="examples/images/medium.jpg" alt="A giant stone face at The Bayon temple in Angkor Thom, Cambodia"> </picture>
The picture element and associated features are W3C standard HTML features that allow web developers to deliver an appropriate image to every user depending on a variety of conditions like screen size, viewport size, screen resolution, and more. Picturefill is a polyfill that enables support for the picture element and associated features in browsers that do not yet support them, so you can start using them today!
A consensus was reached on the spec. Chrome, Firefox, and Opera are implementing it as we speak. Until then (and for other browsers) use this one.