diff --git a/tools/fimgfilters.c b/tools/fimgfilters.c
index 5038db2..904f1a9 100644
--- a/tools/fimgfilters.c
+++ b/tools/fimgfilters.c
@@ -36,6 +36,10 @@ fprintf(stderr, ">>> %s ( '%s' '%s' %d )\n", __func__, infname, outfname, type);
 fimg_show_filter(NULL, &filtre);
 #endif
 
+if (0 != type) {
+	fprintf(stderr, "%s: bad type %d\n", __func__, type);
+	}
+
 if ((foo = fimg_create_from_dump(infname, &src))) {
 	fprintf(stderr, "read error on '%s' is %d\n", infname, foo);
 	exit(2);