Hey thats an image of my great grandparents....! ..only kidding.

Images showing people in street scenes I wouldn't worry too much about (except for crediting XYZ) but portraits I'd check out first. Plus, who would want portraits of someone we don't know? Now, if you were to put a book together with portaits and street scenes from the late 19th century, especially if you know they are from the same locality, maybe with some newer images you have taken (to show change of environment) and promote it as a view from xyz county in West Virginia or wherever, that might sell! Hey, good idea.