You've chosen some very good images to share on your site - the birds in particular really appeal to me.
I like the simple design and easy to follow layout. Not sure if your home page really needs to say 'Home' at the top, although having a title works for the galleries.
You obviously have a pretty large archive, judging by my quick pop over to your stock photo site
. If you were to add more to your website, then my suggestion would be to keep the number of images in each
Gallery category small enough that the viewer doesn't then have to keep scrolling down and down and down... (hope you don't mind me suggesting this, particularly if that's already your plan - and I'm new to all this website stuff myself!).
Rachel