Why are the photos taken by the same person at the same time completely different?

Many people like to take selfies with their mobile phones facing up at a 45-degree angle, which looks beautiful. Some people are funny. They look down at the camera and pat their chins very small. If the same person shoots in two ways, there is a great chance that they are not the same person. In fact, it is easy to understand, that is, the shooting angle. Different angles cause different perspective effects. To put it bluntly, it means near big and far small. Head up, head close to the camera, chin far from the camera (melon seeds