--- netpbm-10.33/converter/ppm/ppmtompeg/fsize.c.ppmtompeg	1995-07-03 23:57:05.000000000 +0200
+++ netpbm-10.33/converter/ppm/ppmtompeg/fsize.c	2006-04-05 12:44:04.000000000 +0200
@@ -117,8 +117,8 @@
     Fsize_Validate(&Fsize_x, &Fsize_y);
 
     if ((Fsize_x==0) || (Fsize_y==0)) {
-      fprintf(stderr,"Frame %d:  size is zero!\n",id);
-/*      exit(1); */
+      fprintf(stderr,"Frame %d: image dimensions need to be integer multiples of 16 for ppmtompeg!\n",id);
+      exit(1);
     }
 
 #ifdef BLEAH