Randomly selecting 8 × 8 host blocks in big-blocks for data embedding, YASS , a recently developed advanced steganographic scheme makes these blocks not coincident with the 8×8 grids used in JPEG compression. As a result, it effectively invalidates the self-calibration technique used in modern steganalysis. However, the randomization is not sufficient enough, i.e., some positions in an image are possible to hold host blocks and some are definitely not. Based on this observation, the newly developed specific steganalyzer  can effectively defeat YASS. In this paper, a new steganographic scheme is presented. Through randomizing the size and position of each big-block, our improved steganographic method makes almost every position possible to hold a host block, which has been verified by our statistical analysis. Consequently, the proposed scheme can survive the attack made by the specific steganalyzer. Experimental results have demonstrated that the detection rate achieved by the specific steganalyzer on our proposed method is less than 58%, while that on YASS is about 95% and above.