Set Partitioning in Hierarchical Trees (SPIHT) is a wavelet based compression algorithm that offers good compression ratios, a fully progressive bit-stream, and good image quality. This paper presents the results of adding arithmetic compression to the SPIHT images in the hopes of further reducing the image size. Both the original SPIHT algorithm and a version optimized for FPGAs were used. Our tests used a model-0 adaptable arithmetic coder and show that SPIHT images can be reduced another 0-5%. Further, the compression ratio was dependent on the bits/pixel encoding level of the SPIHT image and slightly dependent on the symbol length used.