What is steganography?
“Steganography is the art of hiding messages within other messages or data. Most commonly we see this utilized with pictures. This is probably encryption at its finest. Mostly because it doesn't look like usual garbled text that we are used to seeing with encryption…”
For further reading:
https://www.blackmoreops.com/2017/01/11/steganography-in-kali-linux-hiding-data-in-image/