Not difficult to understand why this photo from a family album survived – for at least as long as anyone remembered who these characters were, it must have caused some laughs as it was clearly meant to do.
The style of most of these helmets was used throughout Europe in the latter 19th and early 20th centuries, but a military expert could recognize the crests and say what nationality. I would suggest a pre-WWI date for the photo based on the clothes (yet the one soup bowl helmet looks WWI and the bucket style helmet more reminiscent of WWII). The young boys have bows on their shoes and heavy wool fabrics are being worn even though it is not winter.