The problem at the moment is that images are in formats that are locked to fixed sizes in pixel-counts. There is no good solution while this is true. Either the designer targets an obsolescent screen and wastes most of what many have, or you commit lots of people to scrolling.
Authors can then make rubber page designs that also stretch or shrink to fit the screen.
If this technology catches on, we will see some progress in this direction. I do not hold out much hope for the alternative of simply telling authors to think small.