As the availability and use of digital images increase, the efficient storage of images becomes an important area of research. Traditionally, each image in a set is compressed individually, taking advantage of the redundancies existing within the image. In the related area of video compression, a video sequence is decomposed into individual frames. Video compression algorithms take advantage of redundancy existing among consecutive frames as well as the redundancy existing within each frame. Unlike video compression, there are applications that use large image sets whose inter-image relationships are unknown. For example, a medical database may contain a large number of X-ray images of the same body part; a database of satellite images may possess "similar" characteristics; a database of facial images contains many similar images. In some applications compressed images must be identical to the original images, therefore lossless compression must be used.