I was just on GOG...bought it there too...
Weird because i'm right on the main page and it shows at $42.29...
On my PC it's showing $53.99. But I live in the U.S and not Canada..
Which is supposed to be the newer/better picture? All that is clear is these were taken at different times of day, with the sun facing him from another direction.
The lower pic is from the most recent build, and the difference is more than just the time of day..
In the lower pic, it looks like terrain tessellation is fully enabled, plus the vegetation quality is a bit better.