OK, so they can hide hidden data or compressed images inside an existing image. HOW CONVENIENT! Post an image on a conservative website, and everyone who visits the site has that image in their web cache. THEN, you raid the side, get a list of the visitors, and raid all of them for having “bad pictures of kids” on their computer. DESPITE THE FACT THAT THEY DIDN’T KNOWINGLY DOWNLOAD IT.
Might seem a bit far-fetched, but I wouldn’t put it past them to try it.
Steganography isn't new and Al Queda guys were using these techniques to coordinate amongst themselves using messages hidden in pictures on message boards back in the 2000s. I was playing around with it in the '90s and it's older than that.
If someone wanted to use it to entrap us all they would make it uncrackable. Hypothesis: if you turn someone in for encrypted kiddie porn but you are the only person in the world with the key to break the encryption you might just become a suspect.