Apart from a nicely responsive admin area, WordPress 3.4 now [includes retina assets](http://core.trac.wordpress.org/ticket/20293) for all the icons in the admin area to make them look crisp on devices with high-dpi screens like the iPhone or iPad 3, most flagship Android devices and of course the new ÜberMacBookPro.
There's just one problem: WordPress doesn't include anything to make this easy for developers. The functions `register_post_type()` and `add_menu_page()` only allow you to define one image as menu icon which then gets inserted as `img` tag.
[](/wp-icons-template/)If you want to include retina assets, you have to do it via CSS and media queries. Have a look at the code examples in my [WordPress icons template post](/wp-icons-template/) or peek around in the [github repository](https://github.com/kremalicious/wp-icons-template) to see how this can be achieved.