Safari 6 and Chrome 21 added vendor-prefixed support for the proposed CSS4 image-set specification. This proposed specification is designed to support displays with different pixel densities (read: retina displays).
background-image: -webkit-image-set(url(image.jpg) 1x, url(email@example.com) 2x);
/* Also include other prefixed versions of this ... */
background-image: image-set(url(image.jpg) 1x, url(firstname.lastname@example.org) 2x);
Safari 6 and Chrome 21 add image-set to support retina images →
Related: High DPI images for variable pixel densities →
The CSS4 Selectors spec has already seen a large number of revisions since level 3. As it is still the first draft of the spec, it will likely change in numerous ways before it becomes a recommendation itself and there are browser implementations. Lets have a quick dig into the draft and see what has changed.
What’s slated for CSS4 Selectors? →
Some of the experimental features Tab Atkins — a guy who’s on the Chrome team and part of the CSSWG — is working on (aka how we will most likely write CSS in the near future)