my $background=Image::Magick->new(magick=>"gif");
    $background->BlobToImage($bin_data);
    $background->Set(size=>"100x100+1"); #size and offset of watermark inserted
    $background->Read('stegano:result.gif');

    $background->Write("gif-");
    
    $bin_data = $background->ImageToBlob();
    print "content-type: image/gif\n\n";
    print $bin_data;