As with any other Headcycle click on photos to make them full screen.
Once a photo is fullscreen you can pan vertically or horizontally with your mouse or by tapping your screen.
Here's a good example of an ultrawide image in /h/f8andbethere.
In the background you can hear Baxter the cat expressing his displeasure.
In the background you can hear Baxter the cat expressing his displeasure.