The hexagonal Tech images generally go from having blue to red backgrounds as you go up the Tech tree. This is most apparent under Weapons and Warfare Equipment as the guns get more shooty. The City Centre techs are the one example I can see that follow the opposite; they go from red to blue, and the lowest-level tech has the most people in the picture, despite providing the smallest population bonuses. Are these two images actually the wrong way round?
I think they are! I’ve swapped them on the wiki and have asked for them to be swapped in the game, thanks.