This paper describes a watermarking system that has the robust characteristics against the geometric attacks of resizing and the bitrate varying attacks. While the existing watermark methods of marking on AC in DCT coefficients are weak against the geometric attacks, the methods of tiny increasing the DC in DCT coefficients and the system implementations are suggested in this paper. We measure the differences between the original images and the watermarked images and the detecting rate from the geometric and bitrate attacked images. Results of experiments show that our method is robust against that attacks.