Adaptar imagenes segun resolución /* no testeado */

gistfile1.css

@media (min--moz-device-pixel-ratio: 1.5),
       (-o-min-device-pixel-ratio: 3/2),
       (-webkit-min-device-pixel-ratio: 1.5),
       (min-device-pixel-ratio: 1.5),
       (min-resolution: 144dpi),
       (min-resolution: 1.5dppx) {
 
  img{
		image-resolution: 1.5dppx; 
		width: 50%;
		height: auto;
	} 
}

@media  screen ( min-resolution: 72dpi) {
	img{
		image-resolution: 72dpi;
		width: 100%;
		height: auto
	}
}