The photo gallery guestbook and comments are now enabled. I keep forgetting that everything is off by default.
Nick, you are more than welcome to use that pic as your avatar. In general, feel free to use any of my pictures for whatever you want. To download the original size photo, hover over an image and a popup will appear on the left hand side. Click the "download original" link.
You can also order prints directly from the gallery. They are not marked up and I benefit in no way from people getting prints made.