is there any evidence that the steganography here is undetectable? i would have thought that uniformly random data in the low bits of an image's data (pixels or fourier coefficients or whatever) was a clear signature for anyone trying to find these things. aren't they naturally correlated in various ways?

also, something like tineye can be used to retrieve web-sourced images for comparison, which would make any hidden data really obvious (and a smooth gradient would be even more suspicious if the lowest bits weren't smooth).

what is the state of the art in steganography? is it feasible for reasonable bandwidth? what are the best carrier data to use? do phone cameras provide raw images or are they always jpegs? i guess a webcam video uploaded to youtube has the advantages of large data volume, unique content, and wide visibility. but do they reformat?