The negative of a polarized capacitor is going to be connected to ground. So the capacitor on the right is connected to the positive (red) and negative / GND (black) rails of the breadboard.
The one of the left shares the GND pin of the regulator which looks to be the middle pin. So the cap on the left will connect across the VIN and GND of the regulator.
Ok cool, thanks! But how come the capacitor goes from + to - in both cases? I don't see the reasoning, what is the purpose of doing that?