What is the structure of the picons databases?

Each database is structured as a directory tree. Each directory deeper into a database more specifically references a picon. The databases for users and domains are organized by reversed Internet domainname components followed by the username. For example, my XPM picon is located in the "users" database under my most general e-mail address, kinzler@indiana.edu, in

the file

users/edu/indiana/kinzler/face.xpm

The picon files themselves are always named face.xbm, face.xpm or face.gif. If a face.xpm file exists, then an equivalent face.gif file will also exist, and vice versa. If the picon applies to the domain as a whole and no user in particular, the username "unknown" is used. These picons are typically in the "domains" or "unknown" databases, for example

domains/edu/indiana/cs/unknown/face.xpm