JBIG is an acronym for 'Joint Bi-level Image Experts Group'. This is a group of experts nominated by national standards bodies and major companies to work to produce standards for bi-level image coding.
The JBIG group has developed the IS 11544 (ITU-T T.82) standard for the lossless compression of a bi-level image. It can also be used for coding grayscale and color images with limited numbers of bits per pixel. It is sometimes thought to be similar to Group 3 or Group 4 fax, yet offers between 20% and 80% improvement in compression over these methods. JBIG compression averages about a 20:1 over the original uncompressed image.