my $fn = 'file.dat';
 
 $/ = "AZI\n";
 
 open my $fh, '<', $fn or die "cant stand smell of $!";
 my @images = <$fh>;
 close $fh;
 
 my $num = 1110;
 for my $img (@images) {
    open $fh, '>', ++$num .'.tiff' or die "can't dump image! $!";
    print $fh $img
 }
 
##</code><code>##

  ...
  while( my $img = <$fh> ) {       # read one record
     # [update $fh => $ih]
     open my $ih, '>', ++$num .'.tiff' or die "can't dump image! $!";
     print $ih $img
  }
  ...