pvernon is right. This is the famous Aviatik D.I that was found and restored for/by the Champlin Museum people a number of years ago. The late Dr. Martin O'Connor had a hand in the restoration and especially in the painting of the detailed camouflage scheme. Some people have quibbled with some details of the restoration, but it always looks great to me whenever I've had a close-up look at it. Barrett and Stephen Lawson can tell you a lot more about its history.
It was in the Champlin Fighter Museum in Arizona for quite some time, and is now at the Seattle Museum of Flight (or whatever it's called..). The person who wrote the captions for the website from whence this shot came obviously got their wires crossed. The Museum also has a Pfalz D.XII (also ex-Champlin), and someone who couldn't read Roman numerals captioned this as a Pfalz D13!
Greg
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Greg VanWyngarden
An expert is a person who has made all the mistakes that can be made in a very narrow field. Niels Bohr