Couples' heads, which are easy to understand literally, refer to the heads used to represent couples. Usually people use couples' heads, which are pictures of lovers, men and women, men and women, female ghosts and even cross-racial relations in movies or comics.
Definition of couple's head portrait
Using a couple's head is equivalent to announcing that you are together. When your girlfriend uses the portrait of a couple, she is declaring her sovereignty, telling those suitors who covet her beauty to give up quickly.
The girlfriend's request for a couple's portrait is also based on security. I'm afraid you're too good to be hooked up by a fox, so I want you to use a couple's head. Maybe my girlfriend thinks the couple's head portrait is very beautiful, cute and fresh, so she wants to try it with you.