Modern steganography does more than just use the LSBs of the image. For example, the watermarks used for SDMI (audio, not image data, but same logic applies) u

Modern steganography does more than just use the LSBs of the image. For example, the watermarks used for SDMI (audio, not image data, but same logic applies) used techniques from communications systems like spread spectrum carriers (similar to what you might see with a digital radio system). For images you can also try to place the stegotext along edges and other high-frequency regions where there is more "noise" available to hide what you are doing. If you need to maintain secrecy, you can combine steganography with cryptography e.g. use a PRNG to select carrier frequencies (IANAL but you probably should beware of ITAR issues if you distribute such a thing). You should also give thought to how robust you want the stegosystem to be to image filtering, downsampling, etc. The MPAA uses watermarks on movies to determine which theaters are the source of camrips, and those watermarks have to be as robust as possible (they must survive both the camera's inherent reduction in quality and possible transcoding/editing by the pirates). Not all stegosystems need to be robust, for example SDMI used one robust and one weak in an effort to identify downsampled copies of the audio (the RIAA assumed that downloaded music would always be significantly downsampled).