Everyone used to send photos to each other. We remember that students in high school and junior high school bought their own photo albums, but they didn't have them in college. Originally, it was enough for everyone to build a group and pay attention to their QQ space or WeChat circle of friends. Of course, except for the people in their dormitory, many students in a class in the university can't remember it all. Many people don't sign up for class and like to stay at home. Later, they went out to play and never saw the shadow again.