[nextgen gallery] get_permalink(?)

ciao! i have to call get_permalink funztion to get this url

https://www.website.com/post_title.html?pid=18

I have the title of post and the id of photo

$galleryID = stripslashes(nggGallery::i18n($picture->gid));

	$gallerypage = $wpdb->get_var("SELECT pageid FROM $wpdb->nggallery WHERE gid = '$galleryID' ");

	$post_title = $wpdb->get_var("SELECT post_title FROM $wpdb->posts WHERE id = '$gallerypage' ");

this is the link I have to change:

$out .= '<a href="' . $picture->imageURL . '" title="' . stripslashes(nggGallery::i18n($picture->description)) . '" ' . $thumbcode . ' >';

        $out .= '<img title="' . stripslashes(nggGallery::i18n($picture->alttext)) . '" alt="' . stripslashes(nggGallery::i18n($picture->alttext)) . '" src="' . $picture->thumbURL . '" />';

        $out .= '</a>' . "\n";

I tried so

$out .= '<a href="' . get_permalink().'?pid='.stripslashes(nggGallery::i18n($picture->pid)). '" title="' . stripslashes(nggGallery::i18n($picture->description)) . '" ' . $thumbcode . ' >';

it links to the article if I compose the link it always change it to goto?pid=N

do you know which parameters i have to give to get_permalink function??