guardian/frontend — pull request #3398 by kaelig (2014-03-04 18:21:31+00:00)
Title: CSS optimisations & responsive image abstraction

- [new] `.u-responsive-ratio` helper to create 5:3 ratio placeholders
- [fix] Performance: prevent fromage normal images from upgrading/downgrading at all (since 220px is their original size we don't need to pass them to imager.js)