$> for i in `seq -w 1 100`; do cp originalmono.tiff originalmono${i}.tiff; done

##</code><code>##

 use strict;
 use warnings;
 use Imager;
 
 my $fn='originalmono';
 my $img = Imager->new();
 my $tdiff = time();

 opendir my $dirh, '.' or die "Can't read: $!";
 while( my $name = readdir $dirh ) {
    if( $name =~ /^$fn\d+.+tiff$/ ) {
       $img->read(file=>$name) or die $img->errstr();
       #  *** qtype=>'preview' /  qtype=>'normal'
       my $omg = $img->scale(xpixels=>1024, ypixels=>768, type=>'min', qtype=>'preview');
       #  *** file=>"$name.png" / file=>"$name.gif"
       $omg->write(file=>"$name.png") or die "Can't write: ", $img->errstr;
    }
 }
 $tdiff = time() - $tdiff;
 closedir $dirh;
 print "$tdiff seconds\n"