X-Face

File Format
Name	X-Face
Ontology	Electronic File Formats Graphics X-Face
Extension(s)	.face, .xface
Spec	https://purl.org/x-face-spec
Released	~1990

X-Face is a compressed image format that can be placed in an email or Usenet newsgroup message header. It is expected to contain the sender's picture or avatar. It is a 48×48 bi-level image. The format appears to be fairly complex, and probably uses arithmetic coding.

Discussion

Although X-Face data is often expected to be stored in a file, there isn't really a standard X-Face file format. The main thing to be aware of is that sometimes the "X-Face:" header name is stored in the file, and sometimes it is not. Different software has different requirements.

File extensions .face and .xface have both been suggested. Sometimes, X-Face data will be in a file named ".face" in the user's home directory.

Most or all X-Face code is based on James Ashton's Compface software, and Compface's code is fairly opaque. A specification has been written by reverse-engineering Compface.

Compface intermediate format

The Compface software by default converts X-Face to and from the Ikon format. It only supports 48×48 images with a bit depth of 1. Most implementations use 16-bit words but one implementation[1] uses 8-bit words.

Software

• Compface
  • compface-1.4.tar.gz (uncompface -X to convert to XBM format)
  • compface-1.5.2.tar.gz
  • compface-25Jan90.tar.gz
  • X-Faces for Windows 95/NT
• FFmpeg
• Deark
• Online X-Face Converter
• x-face-el — extends the format, in a manner unsupported by other software, adding colour/greyscale pixels, animation, and larger image sizes

Samples

• https://dev.mutt.org/trac/wiki/MuttGuide/XFace - Search for "compface tao.xbm".
• WinFace1_3-src.zip → WinFace/default_face.txt
• faces man page, "XFACE SUPPORT" section, has an example.

Links

• Faces Archive - Lists some X-Face resources
• faces man page
• Wikipedia: X-Face