The css3-images module is at candidate recommendation. http://www.w3.org/TR/2012/CR-css3-images-20120417/#the-image-resolution I propose to introduce image-resolution, initially behind a compile-time flag. Advertised on webkit-dev: http://thread.gmane.org/gmane.os.opendarwin.webkit.devel/20505 Now that the parsing and style application aspects of implementation are complete, existing javascript tests only cover layout. Add ref-tests to verify that rendering is also correct. As the existing tests already cover parsing and layout, this should be limited to ensuring that: image-resolution: ${x}dppx is equivalent to: zoom: $((1/$x))