I have two suggestions for how to proceed.
The first option involves simply uploading the image, which can then be attached to multiple profiles. This allows people to come across the image while browsing.
Alternatively, a more effective approach would be to create a space page. A space page functions like a profile page, but is dedicated specifically to certain topics, as you mentioned, that are not profiles.
You can upload the pictures and attach them to this space page. If you've already uploaded and attached some images to his profile, there's no need to upload them again; just attach them to the space page.
It would be helpful to include any information you know about the images, and then you can categorize the space page appropriately, such as [[United States, World War II]]. This will facilitate easier discovery for anyone browsing profiles from that era.
If you're unfamiliar with space pages, you can find more information here:
https://www.wikitree.com/wiki/Help:Free-Space_Profile