In each of the places you should look for a point, these points can be on top of vehicles, walls, boxes or even on the floor, check carefully until you find the point of the photograph.
By taking the photograph you will see that you have completed one of the goals. To be sure, check in the city memory option, points that are completed will be marked in red and those that have not yet been completed will be colorless.
At the end of all objectives just look once again at the city memory option and redeem your title and for free you will receive other rewards like gold and map farms.
Note: If you are a low level player ask your friends for help as on the Levi City map there are several extremely strong zombies. Even the most experienced survivors of the game have a little difficulty in this map so cooperation with friends is vital.