Dan, many (I would hope most) of the photos uploaded have a commercial usage ok license or are public domain and are given attribution to the photographer. Some, are commercial license photos that users have generously paid for and uploaded for the benefit of improving their cities on the cityonchain platform and for the benefit of CoC users and the platform as a whole. Some photos are taken by CoC users and put directly onto the platform; I've done it myself as it happens. No one is going to get rich spending time hunting out photos, d/l then u/l to CoC to then receive a few pennies from likes. The CoC city albums can be thought of as a repository of city photos from across the internet that provide a very convenient means for people to appreciate the beauty and wonder of cities from around the globe.