This article describes the uncompressed bi-level image format that is usually called something like Bennet Yee's face format, and sometimes YBM. It does not seem to have an official name. It is the format used by Netpbm's ybmtopbm/pbmtoybm utilities, and is among the formats supported by the Fuzzy Pixmap library (
-B option). It originated with utilities named "face" and "xbm", by Bennet Yee.
Files have a 6-byte header, followed by the image data.
The Fuzzy Pixmap library suggests the file extension .bm.
Files begin with
0x21 0x21 (ASCII "
- Netpbm: pbmtoybm, ybmtopbm
- fbm-1.2.tgz - Fuzzy Pixmap Manipulation Library (see also FBM image)
It would be nice to find copies of the "face" and "xbm" utilities. They are referenced in the man pages of old versions of Netpbm, which suggests that they were publicly available.