diff --git a/lib/fimg-pnm.c b/lib/fimg-pnm.c
index 2d248e6..716623d 100644
--- a/lib/fimg-pnm.c
+++ b/lib/fimg-pnm.c
@@ -227,17 +227,30 @@ switch (plane) {
 		abort();			break;
 		}
 
+if (NULL == ptrplane) {			/* mmmm... */
+	fprintf(stderr, "%s: mmmm...\n", __func__);
+	return -3;
+	}
+
 if (NULL==(fp=fopen(fname, "w"))) {
 	perror(fname);
 	return -2;
 	}
 
+/*               WARNING !
+ *   some software (yes, povray, I look at you) doesn't like
+ *   width and height on two separate lines.
+ */
 fprintf(fp, "P2\n%d %d\n65535\n\n", psrc->width, psrc->height);
+
 area = psrc->width * psrc->height;
 maxval = fimg_get_plane_maxvalue(psrc, plane);
 fk = maxval / 65535.0;
 
-fprintf(stderr, "%s: maxval of %c = %f\n", __func__, plane, maxval);
+if (verbosity) {
+	fprintf(stderr, "%s: maxval of plane '%c' = %f\n", __func__,
+					plane, maxval);
+	}
 
 printed = 0;
 for (idx=0; idx<area; idx++) {
@@ -265,6 +278,10 @@ float		accu;
 fprintf(stderr, ">>> %s ( %p %s %d )\n", __func__, src, fname, flags);
 #endif
 
+if (flags) {
+	fprintf(stderr, "%s: flags must be 0\n", __func__);
+	}
+
 if ( src->type != FIMG_TYPE_RGB ) {
 #if DEBUG_LEVEL 
 	fprintf(stderr, "%s : type %d is bad.\n", __func__, src->type);
@@ -277,7 +294,11 @@ if (NULL==(fp=fopen(fname, "w"))) {
 	return -2;
 	}
 
-fprintf(fp, "P2\n%d\n%d\n65532\n\n", src->width, src->height);
+/*               WARNING !
+ *   some software (yes, povray, I look at you) doesn't like
+ *   width and height on two separate lines.
+ */
+fprintf(fp, "P2\n%d %d\n65532\n\n", src->width, src->height);
 
 area = src->width * src->height;
 maximum = fimg_get_maxvalue(src);