Pretty easy really. Without knowing the key for the steganographic algorithm, it's really hard to get the data out unless you can compare it to the original.

Pretty easy really. Without knowing the key for the steganographic algorithm, it's really hard to get the data out unless you can compare it to the original. So if you're sourcing the pictures from somewhere, you'll need to manipulate false bits that aren't called for from the data itself to keep it from being breakable in such a manner.