This paper describes a new multilevel-decomposition method for the blind source separation of convolutive image mixture. The proposed method uses an Adaptive Quincunx Lifting Scheme based on wavelet decomposition and a geometric unmixing algorithm. It proceeds in three steps. In the first step, the mixed signals are decomposed by an adaptive lifting scheme. The unmixing algorithm therefore applied to the most relevant component. The unmixed signals are, thereafter, reconstructed using an inverse transform. Experiments carried out on images from various origins showed that the proposed method yields better results than many widely used blind source separation algorithms.