poor thumbnail quality
i took a look at some of these and the original photos that are perfectly good and sharp at full size are yielding blurry thumbnails. i played with some sharpening options in imagemagick. it seems like the site does get better image compression from the blurry thumbnails, but i think it goes to far! as an example look at this project:
the quality of the lead full size image is just fine. the 75x75 thumbnail is 1.3k but the quality is really poor (see attached). i re-thumbnailed used a basic unsharp mask (should be available in any image processing package), and i get a far better image (also attached). the new one is 2.5k - but really i think it is worth it.