You can use progressive jpegs without progressive rendering. Google images isn't even using this, they are displaying a very low-res photo immediately, and load

You can use progressive jpegs without progressive rendering. Google images isn't even using this, they are displaying a very low-res photo immediately, and loading a higher quality one in the background. (and FYI, most sites that optimize their images (e.g. Facebook) use progressive jpegs for efficiency).