Steganography is the art and science of writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message, a form of security through obscurity. The advantage of steganography, over cryptography alone, is that messages do not attract attention to themselves, as they look like any normal bitmap or jpeg image. In this paper, we have discussed the security threat imposed by the steganography tools, and the proposed countermeasures. We have developed an algorithm which can compare a stegano image with normal images. Later we have discussed how this algorithm can be used to detect whether an image is a stegano image or not. We have used bitmap images in our research work.