I think this is a clear case of RTFM ;)

Image::Magick will show you that there is a web page set up for this module. And on that webpage it shows you:

To write an image in the PNG format to a PERL filehandle, use:

    $filename = "image.png";
    open(IMAGE, ">$filename");
    $image->Write(file=>\*IMAGE, filename=>$filename);
    close(IMAGE);
[download]

Of course, $filename can contain a specific path.

HTH,