center first & last image ?

goodmorning

Hello! Just discovered zenphoto today, and am excited to use it.

I am trying to figure out why I can't have the first and last photo centered... all the other photographs are centered, but when I am at the first and last images in an album, they are left aligned.

Any ideas as to why this is?
http://www.thepetridish.ca/photography/test-album