How does photography express psychology?

The use of light and color, as well as the performance of characters, can perfectly and artistically show the atmosphere and artistic conception in the later period.

For example, in a deep and single background, someone sitting with his head down shows that he is depressed and frustrated.

Or in the background of blooming flowers, a pair of lovers embrace each other heartily, which shows that this is a happy scene, and it is their happy mood that makes the flowers bloom.