Not pretty. Generally speaking, the most direct and simple psychology is not good-looking. For a good-looking person, if she has a strong vanity, or especially wants to get the attention of others, then such classmates will be happy to expose her photos. I'm afraid others don't know what he looks like, but in fact all his classmates and friends know what he looks like. On the other hand, what about the ugly classmates? There is no need to take it out to dry. Because you know you don't look good, it probably won't bring you much benefit if you take it out. If you take out your real photos, it is likely to cause some unnecessary trouble. For example, many newcomers will judge people by their looks, so you can avoid your own shortcomings first. So this is the most direct reason, which leads many students who are not good-looking to use real photos.