WebKit now supports the
srcsetattribute on image (
img) elements (official specification from the W3C). This allows you, the developer, to specify higher-quality images for your users who have high-resolution displays, without penalizing the users who don’t. Importantly, it also provides a graceful fallback for browsers that don’t yet support the feature.
Too bad Google went and forked WebKit, otherwise Chrome would probably have support for this too.
(via Mr. Gruber)