Along with adding jumbo-sized versions of most of the Myst V screenshots, a new banner has been added to the top of the page. The banner features the cyan worlds logo as well as a random screenshot from one of the myst games produced by cyan.
Most are either from past myst games or from already released Myst V screenshots but there were three I found after refreshing the page several times.
The first is a round room similar to the D'ni shaft screenshot but with a more intricate floor pattern and a pool of water in the center. The lighting in this picture looks much better than previous screenshots.
The second picture shows a snowy mountain. This is probably only a background but the detail is amazing. There is a metal dome with pipes coming out of the top in the foreground.
The third picture in very faded from fog but you can make out a rock in the front with possibly wires attached to it and a huge machine holding three large spheres although there is probably a fourth one out of the shot on top.
Except for the first shot which could posssibly be from the same area as the D'ni shaft, these appear to be screenshots from completely unrevealed ages. One is a cold mountainous factory-like area and the other is a mysterious misty environment with huge machines.
I have all three banners on my computer but I don't have anywhere to upload them(ubi on uses pics from other urls)so you'll just have to look at them on cyans website for yourself. Be patient, there are a lot of different banners. Perhaps there are even more new screens which I haven't seen yet.