Portraits are among the most compelling portraits, let's compare the Flickr image at https://www.flickr.com/photos/redhead_and_wolf/14897199288/in/explore-2014-08-30 with the Aqueti version shown below
The Aqueti image is super-resolved by a factor of 3, corresponding to a 9x increase in effective pixel count. This is pre-calculated and cached on the server to allow rapid exploration. For comparison, here is an interactive version of the original raw image.
Aqueti believes that essentially all online images shown be displayed in interactive zoomable form. The amount of zoom allowed and processing architecture between on line storage and the display device depends on context and image quality, but for high quality images experimental practice and theoretical analysis suggest upsampling by 2-3x will increase the quality of the viewer experience.