Wavelet zerotree encoding has been proven to be an efficient way of compressing still images. Two well-known zerotree encoding algorithms, embedded zerotree encoding (EZW) and set partitioning in hierarchical trees (SPIHT), provide excellent progressive display when images are transmitted over reliable networks. However, both algorithms are state-dependent and can perform poorly over unreliable networks. In this paper, we apply the concept of network-conscious image compression to the SPIHT wavelet zerotree encoding algorithm, to improve its performance over unreliable networks. Experimental results confirm the utility of network-conscious image compression concept.