In this thesis, new steganographic systems employing Least Significant Bit (LSB) technique and Wavelet Transform (WT) for embedding are proposed. These systems incorporate threshold level technique to enhance the performance of embedding scheme. Further, Forward Error Correcting Code (FECC) is used to improve the system performance. In the first proposed system, the cover image is a gray image and the WT is applied directly without coding. The secret image is ciphered for preparing to embedding process. The locations of embedding are randomly selected according to pseudorandom number (PN) sequence. In the second proposed system, the cover image is a color image; the WT is applied directly to each color layer (Red, Green and Blue) separately. The combination between the ciphering process and steganography gives the system high level of security. This idea makes unauthorized retrieval is difficult. Two coded stego systems are proposed in this work. In the first system, the secret image is coded using Reed Solomon (RS) code. The second system uses the product RS code before the embedding process. The usage of these two classes of RS codes is one of the good choices in order to correct possible errors when extracting the secret image. The proposed systems are simulated using MATLAB 8 software package. The simulation results show that the stego image is visually similar to the original one and does not have any suspension about embedded image. The extracted secret image is similar to the original secret image. The results indicate that using three-level Haar wavelet transform increases the capacity of the secret image that can be embedded. Hence, the steganographic goals are achieved in these systems.