Well, they *may* be 35mm (Scope) scans at 4000dpi and then stretched about 2x horizontally and then re-sized with aspect ratio preservation to 1920across
(do not take the color balance as gospel as I don't think 35mm theatrical positive film matches regular 35mm photo positives so colors can only be adjusted by eye and not by IT8 calibration chart which I doubt many people have for that type of film)
Anyway, they offer an exciting hint at what the blu-ray will hopefully deliver, can't wait! (assuming they don't do weird things to them or the compression doesn't rob too much, the blu-rays should actually look better than this, well at least for AOTC/ROTS, since those two were shot in digital at only 1920 across and they have access to that of course so they should be able to do better easily).
Some had questioned whether the blu-ray would even be worth it after Spike, and I think these show that there is plenty of room for the blu-rays to improve over what was shown on Spike. (although showing in HD on TV first does remove a touch of the OMG I am seeing it in HD for the first time feeling I guess)