If I may inject a shameless plug, this is exactly what http://www.pixtulate.com does to serve up responsive images and hi/low res images depending on screen resolution.
Yes, unfortunately we have to rely on a small client side javascript to detect your client's properties but the solution allows you to both upload and reference one and the same image and URL regardless of client and we'll scale, re-sample and even crop on the fly and cache the formatted image for future requests. We are trying to provide an experience as seamless as HTTP content negotiation.
Yes, unfortunately we have to rely on a small client side javascript to detect your client's properties but the solution allows you to both upload and reference one and the same image and URL regardless of client and we'll scale, re-sample and even crop on the fly and cache the formatted image for future requests. We are trying to provide an experience as seamless as HTTP content negotiation.