It is unquestionably difficult, but the idea here is to improve the experience for that smaller percentage while not hindering the majority. Depending on your site, you can do this using CSS media queries so the browser can determine what asset to load. The only disadvantage is an increase in bandwidth utilization for the retina consumers.
Clearly that's not practical for many sites at this time, but the options are there and it's relatively easy to do if your site is built via the spritesheet style.
Clearly that's not practical for many sites at this time, but the options are there and it's relatively easy to do if your site is built via the spritesheet style.