What are some values and limitations of historical photographs?

Okay so I have a project where I have to get a photo from history and write an ysis of the photograph, but I'm struggling to find limitations. The one photograph is a West Berliner taking a sledgehammer and tearing down the wall, and the other image is the image of a mother and daughter talking to each other over the Berlin Wall will East German backround behind it. Any ideas on limitations? Much appreciated:)