Xview (or xloadimage) does not recognize xpm. It does recognize gif and jpg.
/etc/X11/xdm/pixmaps % ls
XFree86.xpm XFree86bw.xpm debian.xpm debianbw.xpm
/etc/X11/xdm/pixmaps % xview debian.xpm
debian.xpm: unknown or unsupported image type
/etc/X11/xdm/pixmaps % xview -config
Image path: /home/iorio/images /usr/local/images
Image extensions: .niff .jpg .jpeg .gif .sun .csun .msun .face .xwd .xpm .pm .xbm .bm .fax .fbm .mac .pbm .pgm .ppm .img .pcx
Filters:
".Z" -> "uncompress -c"
".gz" -> "gzip -cd"
".uu" -> "uufilter -s"
".uue" -> "uufilter -s"
Thank you for your work on Debian.