In this paper, an image steganography system is proposed, in which the data hiding (embedding) is realized in bit planes of subband wavelets coefficients obtained by using the Integer Wavelet Transform (IWT). To increase data hiding capacity while keeping the imperceptibility of the hidden data, the replaceable IWT coefficient areas are defined by a complexity measure used in the Bit-Plane Complexity Segmentation Steganography (BPCS). The proposed system shows a high data hiding capacity (more than 2 bpp in many case), while keeping a high fidelity of stegoimage (more than 35 dB of PSNR). To make the proposed system robust enough to some distortion caused by non-ideal communication channel, we introduce an Error Control Coding to the system, which can reduce the Bit Error Rate (BER) of extracted hidden data when the stegoimage receive some channel distortion.