thumbnails

I am trying to figure out how I can make the thumbnails square and cropped with this plugin. I would like to set up the gallery thumbs as a small group of squares that show a partial image rather than just smaller versions of the photos.

The photos are all different shapes but I would like the thumbnails to be consistent in size and shape that way they fit a grid pattern. is there a way to do this?

http://ww.wp.xz.cn/extend/plugins/lightbox-gallery/