.JBIG2 File Extension
What is a JBIG2 file?
Bitonal image saved in the Joint Bi-level Image Group 2 (JBIG2) format; store the image using black and white with 1 bit per pixel; may be lossy or lossless; enables greater compression than the CCITT Fax Group 4 algorithm; often used for scanned images and faxes; replaces the previous .JBIG specification.
The JBIG2 format separates regions of the image into text, halftone images, and generic regions. This enables the algorithm to optimize compression for distinct areas of the image.
NOTE: Images in the JBIG2 format also use the .JB2 file extension.