power gallery will do this out of the box.
you will need to modify the code to accomplish this.
you will need to modify the properties.php page and add:
array('w' => 132, 'h' => 140),
to the proportional array, then reprocess the images by editing the water mark.
the edit the galleries/grid_lightbox/index.php page,
and change:
$gallery = get_gallery(get_mediarss_url('gallery=' . $pg_id . '&thumb=132c&full=782p'));
to:
$gallery = get_gallery(get_mediarss_url('gallery=' . $pg_id . '&thumb=132p&full=782p'));
so that the thumb nails use the proportional thumbnail instead of the croped thumbnail.