Stego worm

It's unknown to which extent the Adversary can detect presence of steganography in images being sent over the Net. But whatever capabilities they have, they can be jammed. Imagine a worm that spreads from machine to machine, and on the infected machine it finds all suitable JPEG files, generates some random data as source and encrypts them with random key, and stegoes them into the files. In few days or even hours, a sizeable portion of images on the Net contains potentially detectable stegoed encrypted data. Any Chinese want to get immortalized in Internet history?