Have you ever played the game where you and your friends pass a secret message around by whispering it to one another? It's like that, but with pictures! A message picture is when someone sends you a picture that tells you something.
For example, if your mom sends you a message picture of a heart, it means that she loves you very much. And if she sends a picture of a bed, it might mean that you should go to sleep soon.
Just like with words, different pictures can mean different things to different people, but it's a fun way to send messages and express your feelings without using words. It's like a secret code that only you and the person you're sending the message picture to know!