cxpm - Check an XPM (X PixMap) file, versions XPM 1, 2, or 3.
The cxpm program can be used to check the format of any XPM (version 1,
  2, or 3) file. On error, unlike sxpm, cxpm prints out an error
  message indicating where the parser choked. This should help finding out
  what's wrong with an XPM file but do not expect too much from it though. This
  is not even close from being some kind of lint program for XPM. First, it
  stops at the first error it encounters - so several fix and retry cycles may
  be necessary to get your file to parse successfully. Second, cxpm only
  cares about the format. If, for instance, your pixmap uses too many colors for
  your system you still may experience difficulties displaying it. Be warned.
When no filename is given cxpm reads from the
    standard input.
Arnaud Le Hors (lehors@sophia.inria.fr)
Copyright (C) 1998 by Arnaud LE HORS.