() Mario Lang <mlang@delysid.org>
() Tue, 20 May 2014 17:05:54 +0200

   We currently need XPM format, as %c-%p.xpm, where %c is either
   black or white, and %p is one of pawn, knight, bishop, rook,
   queen and king.

I just added package ‘xpm’ to ELPA.  Maybe you could use it to
"compose" (algorithmically create) these pieces?  Here's a snapshot
of wip gnugo-d0.el, which does just that, for (ELPA package)
‘gnugo’: