If you find photos there, that’s the result of workarounds used by others. In any case, that’s not acceptable and I remember a communication earlier that such kind of violations may lead to a moratorium on the account.
As indicated by @C_T , you cannot add photos of a city.
Btw, the algorithm of Google Maps will show you, when you visit the city in Google Maps, photos uploaded by the users on the various POIs of the city.
Of course, there is also some Local Guide who use a workaround. BTW, this is a strictly forbidden procedure, that can lead to the suspension from the program
I think of it like this: Google selects some images to be displayed under a city from the places inside that city. This happens automatically. That is why your images sometimes get seemingly unexplainable views. I’m not sure but I like to believe that the automated routine, does favor the better images. So often it can be fun to check the “By you” card under your city to see if any or which of your images got selected.
It’s a nice way to get some simple feedback on your work as a Google Maps photographer.