Convert "Complete National Geographic" CNG files to JPG for use under Linux
copying from CD into local hard drive:
cng2jpg.py --src /run/media/_user_/CNG_DISC1/disc1/images --dst ~/CNG/discs/images
convert a hard drive copy
cng2jpg.py --src ~/CNG/discs [--remove]
Use --remove to get rid of .cng files as they are converted, to avoid needing extra 40+Gb of space for both jpg and cng.
"The cng files are all jpegs, XOR'd bitwise with 239"