The end result of encryption is a completely random string of bits. If you replaced an images raster with a properly sized blob of encrypted data (0 padding could be used pre-encryption to get the right size), you would get an image of pure static.
So if you randomly generated a stream of bits and put that in a photo, that would not be differentiable from an encrypted blob inside of a photo data structure.
That means the question is where do you hide a random string of 1's and 0's without it being obvious there is a string of 1's and 0's. The related question to a noisy photo is, is there structure to the noise? Random 1's and 0's is the opposite of structure. So trying to de-steganogra-fy a photo means looking for absence of structure.
This leads to the observation you are making, which is that the photo you choose has a great effect on the effectiveness of the stenography. If you photo-shopped together an image of a TV displaying static, you could put an encrypted blob in the static with all bits and have a cohesive photo. If you were to hide a payload in a completely black (#000000) picture, any strategy used would likely be obvious.
Stenography is very much "security through obscurity" compared to encryption which is security. The nature of encryption means that stenography is primarily about plausible deniability rather than being technically effective.
So if you randomly generated a stream of bits and put that in a photo, that would not be differentiable from an encrypted blob inside of a photo data structure.
That means the question is where do you hide a random string of 1's and 0's without it being obvious there is a string of 1's and 0's. The related question to a noisy photo is, is there structure to the noise? Random 1's and 0's is the opposite of structure. So trying to de-steganogra-fy a photo means looking for absence of structure.
This leads to the observation you are making, which is that the photo you choose has a great effect on the effectiveness of the stenography. If you photo-shopped together an image of a TV displaying static, you could put an encrypted blob in the static with all bits and have a cohesive photo. If you were to hide a payload in a completely black (#000000) picture, any strategy used would likely be obvious.
Stenography is very much "security through obscurity" compared to encryption which is security. The nature of encryption means that stenography is primarily about plausible deniability rather than being technically effective.