In this paper, multiwavelet transform is used in the context of image sharing employing the SPIHT-generated bit stream with the modified Shamir's (r, m) threshold scheme over the Galois field. This provides multiwavelet-based embedded shadow images for progressive transmission and reconstruction. Both integer multiwavelet transform and balanced multiwavelet transform are considered in the method. It is secure and fault-tolerant, and gives small shadow size and excellent rate-distortion performance. Experimental results and sample applications are given to demonstrate the characteristics of this method.