$NetBSD$

--- src/picture.c.orig	2006-04-26 10:39:13.000000000 +0930
+++ src/picture.c	2006-04-26 10:39:36.000000000 +0930
@@ -48,13 +48,13 @@
 
 	p += 4;
 
-	while (isdigit(*p))
+	while (isdigit((u_char) *p))
 		*w = (*w * 10) + (*p++ - '0');
 
 	if (*p++ != 'x')
 		return FALSE;
 
-	while (isdigit(*p))
+	while (isdigit((u_char) *p))
 		*h = (*h * 10) + (*p++ - '0');
 
 	if (*p == 'C') {
