The sight of someone's fingers intertwined within the spokes of a bike must be the visual equivalent of nails on a chalkboard because this photo, viewed large especially, made me actually flinch!

P.S. And I'm guessing your hunch about these two being war veterans is a sound one...here's hoping they made buckets of money and had tons of fun with their bike tricks.

Yes, most modern, and ancient, bicycles have a front sprocket that is several times the size of the rear sprocket. However, this bicycle is a very specialized one, designed for doing trick riding. Having this small front sprocket allows one great control at low speed (the only speed required for trick riding). Modern "trials" and other trick bikes have the same kind of gearing.

About the saddle, which looks rather more like a baguette, I have no idea.

That's one heckuva track stand!

I wonder how pedaling energy and speed is affected. Most modern bikes now have a drive sprocket that is several times as big as the driven one. Seems like it would be a bear to get moving up to speed. With one leg no less.

I can't imagine the trick he is trying to perform here, the handlebars are straight, the tire is at a 90 degree angle and he is pulling something from his back pocket. And the calm look on his face shows he knows exactly how this is going to end.