IBG convert
Reverse-engineered converter for a long-lost IBG image format.
To my knowledge it is only used in a "Invitation au voyage" CD-ROM related to this exhibition:
Invitation au voyage La photographie humaniste française et la photogrphie neoréaliste italienne. Napoli, Castel Sant'Elmo, 23 Gennaio - 7 Novembre, 1993.
The format appears to be a BMP V3 format with a different signature.
Regardless of the header,
however, the data section appears to be
compressed with a non-standard algorithm analog to PackBits.
All of the available examples are 8-bit RGB indexed.
The format seems related to a Windows 3.1 DLL named ibg.dll.
The reverse-engineered algorithm decodes to an equivalent indexed PNG
using the pypng module. Succeeds with 950/959 files, so that there
may still be some edge cases left. The missing files are not decoded
by the native application, either.