The photographs are normally presented in the form of a slide show. The slide show can be started/stopped by clicking Play/Pause at the bottom right of each picture. Whether or not the slide show is on or off you can advance to the next picture or go back to the previous by clicking the right (next slide) or left side (previous slide) of the picture itself. When you hover over the picture you will see a small "Next" or "Prev" white marker appear top left/top right.