There is a very interesting puzzle on the Programming Puzzles and Code Golf site to Rearrange pixels in an image so it can't be recognized and then get it back. I understand that this is not cryptography, but I wonder how effectively a message could be hidden in such an image and then securely transferred and retrieved.
Consider Alice and Bob who have conspired beforehand to use one of the solutions to the puzzle for Alice to transmit to Bob images of text. The TLA* is tasked with breaking their ad hoc "encryption" (obfuscation), but do not know about Stack Exchange sites. The TLA does not have access to Alice, as she is outside their jurisdiction. Furthermore, being images of text, the whole image is in greyscale.
If the TLA were to intercept an image 'encoded' with one of the solutions to the Code Golf contest, what steps would they take to decrypt it?
* TLA: Hypothetical government agency with access to the network.