For a long time the development team at MSDN have been hinting about the work towards work on the responsive image element and now it;s official. They have begun work on implementing the srcset attribute for image elements focussing initially on the x descriptor to provide higher resolution images
specifically for device DPI.
Thankfully they’re also going to include the sizes and
<picture> element features in the future as well.
To take advantage of high resolution screens, it’s desirable to provide higher resolution image resources. While today’s devices come with all sorts of different resolution screens, it’s important to be able to provide the right resource for the device’s capabilities for optimal experience and performance. We have therefore begun work on implementing the srcset attribute for image elements, enabling alternate image resources based on the device’s DPI scaling factor:An excerpt from Status roadmap update: srcset,
element, and date inputs in development