Looks nice and simple. Like the option of changing the text size at the top. A few things I would change:
Don’t link to flicker with your image. I didn’t appreciate having to click ‘back’ to return to the site. Maybe use a text link or something.
Have your ‘next button visible at the top next to your image.
Don’t hide the ‘recent posts’ list. I thought you had nothing but the tree photograph on your site at first.
Clicking on ‘read on’, I expected something about the picture to read, not just photographic information (but this might just because I don’t photoblog.
Sorry it’s a bit negative! The site is by no means bad! Keep going ??