my $size = (-s $filename);
# get extension for mime type
  $filename =~ m/\.([^.]+)$/;
  my $image_type = "image/$1";

  print $cgi->header(
        -Content_Type        => "$image_type",
        -Content_Disposition => "attachment; filename=$filename",
        -Content_Length      => $size,
        -Expires             => 'now',
        );

  open(IMG, "<$filename") || die "Cannot open file: $!";
# not needed under linux ??
  binmode(IMG);
  while( <IMG>) { print; };
  close(IMG);