Callifre

I just got the game for Mac and I have to admit it's pretty fun, but I encountered a problem yesterday. When I attempted to purchase something for my city, none of the images of the assets were shown. All I had was a grey background. I've attached a picture to show what it looks like. I can still hover over the image to find out what it is and buy it but it's tedious. I was wondering if there was a fix for this bug. Any input would be greatly appreciated.