Question

which best describes the way photographs are considered by historians?

Answer 1

I believe this is more of a critical response type of question where you are expected to give a best all around answer instead of a clearly defined structured one.
Based on my experience in taking Dual-Enrollment British history and routinely using my Norton Anthology of English Literature book I would say this...
Photographs are seen by historians as ancient pieces of artifacts. It gives them a general sense of what it was like back in that time; how the culture progressed; the customs of the people; things like that. Most importantly of all, a photograph is a look into the past; something that can analyzed and critiqued.