You're looking at a stunning example of something astronomers and stargazers called "Earthshine." Known by some as "the old Moon in the new Moon's arms," Earthshine is a phenomenon first formally described by Leonardo da Vinci some 500 years ago.
Da Vinci wrote:
Some have believed that the moon has some light of its own, but this opinion is false, for they have based it upon that glimmer visible in the middle between the horns of the new moon...this brightness at such a time being derived from our ocean and the other inland seas — for they are at that time illuminated by the sun, which is then on the point of setting, in such a way that the sea then performs the same office for the dark side of the moon as the moon when at the full does for us when the sun is set....
That's right — what you see here is a Moon illuminated not only directly, by the Sun (the bright, glowing crescent), but indirectly by sunlight reflected off the Earth (the purple glow of Moon's surface that is typically shrouded in darkness).
This particular photograph was captured on March 20th by photographer M. Taha Ghouchkanlu from Esfahan, Iran. You can read more about Earthshine over on NASA. You'll find a hi-res version of the photo up top by clicking here.