my $image_name = 'foobar.jpg';	#from user
   my $upload_dir = '../clients/images'; #hard coded
   
   $self->make_thumb($image_name, $upload_dir, 'jpeg');
   
   
sub make_thumb {
   my $self = shift;
   use Imager;
   
   my ($image_name, $upload_dir, $file_exten) = @_;
   
   ........ imager stuff here ..........
   
   $image_name =~ /^(\w+)\.(\w+)$/;
   $image_name = $1;
   my $to_write = $upload_dir.'/'.$image_name.'_thumb.jpg';
   #$to_write =~ /(.*)/; $to_write = $1; #this didn't help

   $img->write(file=>$to_write, type=>$file_exten)
         or $self->push_error("Cannot write thumbname because: $!");
}