Ian- that's just the way the website works. I'm using the Visualserver template - I don't remember if there is another option for the navigation. I can play around with the settings and see if there is a way to dock the scroll at the bottom to keep it always visible.
Barry - I'm certainly open to editing the images and their sequence. I know what you mean about the menu headings - to have no subcategories seems a little off compared to the others, but I don't know that "portraits" really needs a subdivision. I could in theory do a "color" and "black-and-white" subcategory, or a "studio" and "environmental", but then the categories wouldn't balance well in terms of numbers of each.