[whatwg] Media queries, viewport dimensions, srcset and picture

[Andy Davies]

In Scott Jehl's latest example of a responsive image polyfill
(https://github.com/scottjehl/picturefill), he produced a variation
that allows a non-retinae image to be downloaded by default with the
user having the ability to then choose the download the retina version
of image if then wanted.

Which ever solution to the responsive image eventually get's
incorporated into the spec I think we need to account for this
behaviour at the user-agent level i.e. if the UA decides to download a
non-retina image because the user is on a cell network, then they need
a way of easily choosing to download the retina image if they want.

Any thoughts?

Andy