nextgen gallery horizontal layout

Hi I’m new to all this stuff but studying webdesign at the moment , I’m having problems with the nextgen gallery as when I’m logged in to admin the thumbnails display horizontally but when I logg out of admin it starts going back to vertical, I’ve been into the css with firebug and it says that it is floating left but when I go into an older browser I found 1 that worked. Help I’ve been trying to figure this out for 2 days the link to site is uploadbrighton