It's a slice of Americana in almost every family photo album: A picture of the old folks standing in front of their home. Such portraits — whether they display pride in achieving the American dream or betray the photographic need for outdoor lighting — were all the rage, particularly in the late 19th century.

But nostalgic feelings aside, what can you learn from a photograph that reduces your great-aunt to the size of an ant? Plenty: Dwell on the right clues, and a homestead portrait forms a sturdy foundation for your family research.