change height in link

Is there a way to all changing the heightxwidth in the link? The single setting of dimensions is too restrictive as I have one area where I need the greybox to be small and another where I need it large.

I found this http://drupal.org/project/greybox_5_5 (see the link to the 5.5 project page) but have not tried it as we already have your this installed and on our production environment.