This paper proposes a simple and symmetrical scheme for the prediction and update operators in quincunx lifting, which is then applied into image coding based on Embedded Zerotree Wavelet (EZW) algorithm. In addition, we present a new strategy for taking quantization threshold by combining the power of 2 with the square of integer. The former is used for image coding at higher bit rates and the latter at lower bit rates. The experimental results demonstrate that the proposed method can improve the quality of the reconstructed image.