JBIG is a highly effective lossless compression algorithm for 
high-resolution bi-level images (one bit per pixel), which is 
particularly suitable for scanned documents or fax pages.

JBIG-KIT provides a portable library of compression and decompression
functions with a documented interface that you can include very easily
into your image or document processing software. In addition, JBIG-KIT
provides ready-to-use compression and decompression programs with a 
simple command line interface

IMPORTANT NOTICE

It seems that some of the JBIG algorithms implemented in JBIG-KIT were
or may be still covered by patents. JBIG-KIT comes without any patent
license as its author is not sure which patents affect which use of 
JBIG in which country. With this being said, you should compile and 
use JBIG-KIT on your own.