--- WindowMaker-0.92.0/wrlib/nxpm.c~	2004-10-12 20:21:53.000000000 +0200
+++ WindowMaker-0.92.0/wrlib/nxpm.c	2013-11-07 13:40:23.762829654 +0100
@@ -644,9 +644,9 @@
             if (!a || *a>127) {
                 tmpc = lookfor(colormap, (unsigned)*r<<16|(unsigned)*g<<8|(unsigned)*b);
 
-                fprintf(file, index2str(buf, tmpc->index, charsPerPixel));
+                fprintf(file, "%s", index2str(buf, tmpc->index, charsPerPixel));
             } else {
-                fprintf(file, transp);
+                fprintf(file, "%s", transp);
             }
 
             if (a) {