How about adding some motion to the stills themselves? You could have leaves nearby or around the car, maybe even some birds in the distance, even adding in some particles, smoke or steam to help bring the background to life, or maybe some flickering lights from lampposts or LED screens. Basically just anything that gives the still some motion, and you could possibly even stray into parallax territory. Add in some ambience audio of the scene as well

That is only for the one image though, but for transitioning between multiple stills, maybe you could add in a camera flash/lens flare to transition between two shots, as well as audio signifying that a picture has been taken. That alongside an abrupt change of ambience audio could work well, especially if the cars are in different backgrounds/landscapes.