In this paper we analyze and test several steganographic techniques on still images.
We show that embedding a large amount of data into the picture it can modify
its visible properties. We compare the RSA and the elliptic curve (ECC) based
digital signatures, and we analyze their advantages and disadvantages in
steganography. In steganography it is important that the embedded data size should
be minimized. Using ECC minimization of the embedded information is possible,
because the minimal block size is smaller than in the case of RSA