OK, get out of the car and go up the stairs to the roof. In the far back corner is a red spot - stand there. When you do it automatically brings up your camera.

The trick is to scan the area at zoom out level, then zoom in when you see someone. The first guy comes into the parking lot to the left of the building. Zoom in on his face then press CIRCLE to take the picture. Another car comes into this same spot - take his picture too. A third guy comes in on the right side, get his photo. The fourth guy then comes in from that same right bottom area and is hard because his face is only shown for a few moments. Once you get his photo, you're set.

Cesar says to split up and meet back at the garage. You're abandoned out here!

Mission passed!
respect +

Grand Theft Auto San Andreas Walkthrough