If you're talking about thumbnails, I think they made the right choice. Just the top part of the homepage already contains 5MB of image assets. Scrolling down a few times quickly ups that to 15MB and more. I'd rather have reasonably sized and optimized images throughout the site - with high resolutions ones as downloads - and a very speedy browsing experience, then the other way around.

However, I would expect the online tiled image viewer to show the full, high quality image - at least, when zoomed in.