DjVuLibre is an open source implementation of DjVu, including viewers, decoders, simple encoders, and utilities. DjVu is a web-centric format and software platform for distributing documents and images. It features advanced technologies such as image layer separation, progressive loading, arithmetic coding, and lossy compression for bitonal images, allowing for high quality, readable images to be stored in a minimum of space.
WWW: http://djvu.sourceforge.net/