[FairOpinion]

Yes, it'a a beautiful picture. And it is authentic.

I saw it at snopes.com, a site which researches and posts whether info/pix going around on the internet are verifiable or hoaxes. They say this picture is authentic.
Here is their "Photo gallery" info site: http://www.snopes.com/photos/photos.htm

Here is what they say about this picture:
http://www.snopes.com/photos/azflag.htm

They also have a few other amazing pictures, which are real, sorry, I have to learn how to post pictures, one of these days:

Sunrise through the WTC:

http://www.snopes.com/photos/wtc.htm

Floral US Flag:

http://www.snopes.com/photos/floral.htm

US Map and "God Bless America" in the cornfields:
http://www.snopes.com/photos/godbless.htm

[csvset]

I have to learn how to post pictures, one of these days:

Help on Posting Photos here