They're stencil-printed in three colours, but the artwork is unlike that of any other pack I own. I wish I had the other four pictures, I'd get it framed; as it is, it's incomplete so I can't.
Judging by the art style, I'd guess it was from the 1930s; the printing method, square corners and lack of indices would date it older than that, but it's the wrong subject matter. I really like what they did with it, though.
Why don't they make packs of cards like that today?