if ($OSNAME =~ /linux|unix|bsd/i){
   require Tk::PNG;
   $image = $pic_window->Photo("button", 
      -file => $photo_name, 
      -format => 'png');
}
elsif ($OSNAME =~ /win/i ){
   require GD;
   require Tk::JPEG;
   require MIME::Base64;
   my $im = GD::Image->newFromPng($photo_name);
   my $img = MIME::Base64::encode_base64($im->jpeg());
   $image = $pic_window->Photo("button", 
      -data => $img, 
      -format => 'jpeg');
}

my $label= $pic_window->Label(-image => "button");