The grafitti artist is world famous and likes attention. He probably sent it himself. Read the original article and google his name: grafitti artist DS....
I followed your suggestion, and found the guy's website where he refers to himself as a "stencil artist" - which would explain the overlay of the photo with the image. And, yeah, I guess he very well could have forwarded the image to whomever first wrote the story; so I'll just shut up now.