> that's 4x the pixels (and bytes.) In my experience the 4x pixels works out to something less than 4x bytes assuming jpg or 24bit PNGs because the compression

> that's 4x the pixels (and bytes.) In my experience the 4x pixels works out to something less than 4x bytes assuming jpg or 24bit PNGs because the compression gets more efficient. For instance quadrupling the number of pixels generally doesn't increase the color table by 4x. I just calculated the difference for about 100 retina files on my sites/apps, and the average size increase is 1.8x.