Pictures act to teach, and to evoke emotion from their viewers.
The picture of the man on the moon evokes a feeling of pride from its viewers, knowing that their country was the first transport humans successfully to the moon. They give some people a new sense of appreciation for things that came before them. The picture of John F. Kennedy Jr. brings out emotion in its viewers as it captures him saluting his father in his funeral procession as it passes by. They record life at a specific time and can be used for reference or evidence in the future. The photo of Martin Luther King Jr. evokes pride from its viewers, and also allows them to reflect on the progress that the U.S. has made dealing with Civil Rights in the past 60 years.