These are 256x256, we could use higher resolution version of these. 512x512 would be a good start.
The Urban ones look very poor.

page-9-player-buildings-bases-urban.png
page-6-features-arizona.png
page-6-features-urban.png
page-7-barbarians-arizona.png
page-7-barbarians-kevlar.png
page-8-player-buildings-bases-rockies.png
page-8-player-buildings-bases-urban.png
page-9-player-buildings-bases.png
page-9-player-buildings-bases-rockies.png