I think I know what do you want, you can implement this but this seems to be the starting point.

#!/perl/bin/perl

use CGI qw/:standard/;
use CGI::Carp qw/fatalsToBrowser/;

use strict;
use CGI;


my $got_img=param('myimage');
my $count;

print header();

print "test<br>";

print "<form action=check.pl\n";

print "<br><input type=checkbox name=myimage value=1>1<br>\n";
print "<input type=checkbox name=myimage value=2>2<br>\n";
print "<input type=checkbox name=myimage value=3>3<br>\n";
print "<input type=checkbox name=myimage value=4>4<br>\n";
print "<input type=checkbox name=myimage value=5>5<br>\n";

print "<input type=submit value=submit><br>\n";

print "** $got_img **<br>";

for ($count=0; $count<$got_img; $count++)
{
 print "<b>$got_img</b> \n";
}
[download]

Good luck!