I don't own any retina display devices, but i occasionally do web design. I keep hearing about how most images on the internet look low quality on retina displays, so i was wondering what i should do to make sure that images that i upload online look decent on retina iPhones, iPads, and the new MacBook Pro. Should i make sure all images i export to put online be over 326 ppi? For example, when exporting a pdf as a png in preview, the default resolution is 150 pixels / inch. Do i have to increase this to 326 ppi to ensure that the PNG will look all right even on the new retina MacBook Pro? When exporting an Adobe Illustrator file as a PNG, the High setting when choosing a resolution is 300 ppi. Will this look all right on the 326 ppi retina MacBook Pro display?