War ships official pictures

[stuka f]

Also need some help here.
Found nearly 30 pictures, of different size's and bearing different stamps of different nations, what might they been used for?
I am not putting all pictures here, just 3 with different back stamps (Italian, French and Dutch)

[HARRY THE MOLE]

I would hazard a guess and say they might have been used to train in the identification of vessels from differing nations.

[Gunny Hartmann]

I would hazard a guess and say they might have been used to train in the identification of vessels from differing nations.

Sounds feasible to me!...