diff --git a/contrib/pngminus/pnm2png.c b/contrib/pngminus/pnm2png.c
index 8c3023f660..d51551dd8f 100644
--- a/contrib/pngminus/pnm2png.c
+++ b/contrib/pngminus/pnm2png.c
@@ -537,6 +537,11 @@ int fscan_pnm_token (FILE *pnm_file, char *token_buf, size_t token_buf_size)
   }
 while ((ret == '\n') || (ret == '\r') || (ret == ' '));
 
+  /* read string */
+  do
+  {
+     while ((ret == '\n') || (ret == '\r') || (ret == ' '));
+
   /* read string */
   do
   {
@@ -560,7 +565,7 @@ while ((ret == '\n') || (ret == '\r') || (ret == ' '));
   }
   while ((ret != '\n') && (ret != '\r') && (ret != ' '));
 
-  token_buf[i] = '\0';  // TO NULL-TERMINATE
+  token_buf[i] = '\0';  //  TO NULL-TERMINATE
 
   return (i > 0) ? 1 : 0;
 }