Simple CMS / Gallery for Photography Site

I'm a web designer that is currently building a small website for a photographer. I'd like, if affordable and possible, to have a developer build a CMS system where the photographer could log-in, and upload their own photos to a gallery (There would be 6 to choose from: Portrait, Still Life, Fine Art, Wedding, Events & Children). I'd like the photo to just show up as a thumb, and when clicked on open up neatly (Maybe using one of those nifty AJAX gallery things). I'd like to hear how you'd do it and such. Please PM me with your system and how the gallery would view. I'd be doing the design and putting the pages together, so it would just be implementing the system.