[dan1234]

I wouldn't be too concerned on the app front. The situation was the same when the iPhone first got its retina display but these days most apps are optimised for it.

The web side of things is a different story. AFAIK, there isn't even a nice way to send hires images to hires displays without adversely affecting those browsing with standard DPIs.

[M4v3R]

http://mir.aculo.us/2012/06/26/flowchart-how-to-retinafy-you...

[egze]

There is. -webkit-image-set

[bwilliams18]

I believe apple came up with a tricky way of doing this on their homepage.