# main.pm
...
    my $client_id = "73737";
    my $get_image = thumbs::get_thumbs($client_id);
    $content .= "<img src='".  $get_image ."'>";

    return $content;
}
...


# thumbs.pm
package thumbs;

use strict;
use CGI::Carp qw(fatalsToBrowser);
use CGI;

sub get_thumbs {
    my $client_id = shift;
    my $q = new CGI;

    my $path = "/opt/www/images/";
    my $file = "/img_1.png";

    my $image = $path ."". $client_id ."". $file;

    print $q->header(-type => 'image/png');

    open IMAGE, $image or die "Cannot open $image $!\n";
    binmode STDOUT;
    print <IMAGE>;
    close IMAGE;

    return;
}
1;