diff --git a/Modules/pixrgb.f90 b/Modules/pixrgb.f90
index e7f82e8..8218d90 100644
--- a/Modules/pixrgb.f90
+++ b/Modules/pixrgb.f90
@@ -116,12 +116,14 @@ end subroutine
 !-
 !          CAUTION: there was NO out-of-bounds check !
 !-
+!     The width of the picture MUST be a multiple of 4 !
+!-
 subroutine rgbpix_spit_as_pnm_16(pic, fname)
 
   type(t_pixrgb), intent(in)       ::  pic(:,:)
   character (len=*), intent(in)    ::  fname
 
-  integer                          ::  io, ix, iy, ik
+  integer                          ::  io, ix, iy
   integer                          ::  buffer(3*4), ptr
 
   ! write(0, *) ">>> subroutine rgbpix_spit_as_pnm_16"
@@ -150,7 +152,7 @@ subroutine rgbpix_spit_as_pnm_16(pic, fname)
     enddo    ! write(io, *) " fin iy=", iy
   enddo
 
-!   may be we have to flush the buffer ?
+! XXX  may be we have to flush our internal buffer ?
 
   close(unit=io)