Default User Photo

When calling any of the userphoto_* functions, the 4th argument is the default photo to be used:

userphoto_the_author_photo(
    "<span class='img'>My photo:",
    "</span>",
    array('class' => 'thephoto'),
    get_template_directory_uri() . "/images/default.jpg"
);

It would be nice if there was an option in settings for User-Photo to define what picture should be used as the default photo (with an upload-function as well). Or if a default photo should be used at all even.

Thanks!