What’s all this about “Their Photo [sic]”, anyway? They weren’t all alive at the same time, so it would have been impossible for them to appear together in a single photo.

There are photographs of the soldiers from the Battle of Waterloo in 1815

Now the astute may recall that photography wasn't invented until the late 1830s and wasn't a practical thing until the late 1840s. 

What happened was in the 1840s/50s a photographer got hold of some of the French soldiers who survived, I think mainly the Imperial Guard,  and photographed those who had still kept their uniforms.  So they have photos in uniform of the Imperial Guard from Waterloo. Even if they uniforms were a little ill-fitting some 35–40 years later.  I will have to see if I can find them on-line,  I am sure Stanley Kubrick found them for his film about Napoleon that never go made.