the html file and image file arrive as attachment's not as the message.

The problem is that you picked the wrong example from the documentation. Here's the one to model it after:

        $sender->OpenMultipart({to => 'Perl-Win32-Users@activeware.foo
+',
                                subject => 'Mail::Sender.pm - new modu
+le'});
        $sender->Body;
        $sender->Send(<<'*END*');
        Here is a new module Mail::Sender.
        It provides an object based interface to sending SMTP mails.
        It uses a direct socket connection, so it doesn't need any
        additional program.

        Enjoy, Jenda
        *END*
        $sender->SendFile(
         {description => 'Perl module Mail::Sender.pm',
          ctype => 'application/x-zip-encoded',
          encoding => 'Base64',
          disposition => 'attachment; filename="Sender.zip"; type="ZIP
+ archive"',
          file => 'sender.zip'
         });
        $sender->Close;
[download]

You want your HTML in the body, not as an attachment.

-- Randal L. Schwartz, Perl hacker