Greydragon - resized thumbnails and centering image

Hi there.

I recently installed Gallery3 and am really enjoying the greydragon theme and experimenting with making edits.
There's one thing I've been stuck on for a few days though. I've resized the thumbnails to 175px and I can't figure out how to center the thumbnail image within the thumbnail itself. The landscape images sit slightly lower than they should do and I don't know how to change this.

I also noticed that the link does not cover that top bit of the thumbnail, and wondered if anyone knew how to extend this upwards (or even to cover the whole box, it'd be nice to have the album title a clickable link too).

If someone could take a look, that would be great. I haven't looked much at the HTML, maybe I need to make an edit there?

Please excuse the mess of the site, it's very much in progress!
www.annanielsson.com/gallery3

Thank you