From the Pixelpost introduction:
Meet Pixelpost, a small photoblog application that’s a no-brainer to set up and use. It’s perfect for anyone wishing to regularly post their photos on the web like a blog.
Unlike other blog engines out there, Pixelpost doesn’t try to solve all of the worlds problems. Pixelpost simply does photoblogs, and it does them well. If you are looking for a full blown CMS or text-blog, Pixelpost isn’t for you. But if you want something simple, and designed from the ground up for photobloggers, like yourself, you’ve found the perfect app.
Pixelpost is free to use, and is open-source software.
The Pixelpost templating system is a little klunky, but I like that the system is easily extended through the use of addons (the addon concept is similar to WordPress plugins). Check out Pixelpost.