images display retina

images-display-retina.js

<img src="http://www.site.com.br/nomedaimagem.png" class="hires">
if (window.devicePixelRatio >= 2) {
	var images = $("img.hires");
	// loop through the images and make them hi-res
	for(var i = 0; i < images.length; i++) {
		// create new image name
		var imageType = images[i].src.substr(-4);
		var imageName = images[i].src.substr(0, images[i].src.length - 4);
		imageName += "@2x" + imageType;
		//rename image
		images[i].src = imageName;
	}
}