XBM (X BitMap) is a file format for bi-level raster images, originally associated with the X Window System. It was, and to some extent still is, widely supported by graphics software.
An XBM file is plain text, and doubles as a fragment of C programming code. The format is very inefficient in size, but it can be useful as a simple way to embed an image into a C program.
- X Window System: XReadBitmapFile & XWriteBitmapFile in libX11
- Netpbm: pbmtoxbm, xbmtopbm