I have to agree with CreepyJoe. I work in a studio where we deal with digital images all the time. It might be a fake, since a image manipulation pro using Photoshop can fool anybody.
But like what was forementioned, the distortion around the areas of sharp colour change in the photo are called "artifacts". They're the result of JPEG compression, which is a "lossy" form of compression that removes image detail and reduces image file size by grouping areas of like colour together in small blocks. Try that with any photo where there is strong, sharp contrast between colours (similar to Watson in front of the sky blue background). Make sure you've got the best quality image possible before you start (maybe scan a photo at 300 dpi or better). Now, try saving it as a JPEG image at various levels of compression. You'll see that the higher the compression is, the more chunky-ness you'll see around image edges (the same thing that's happening in the photo of Watson).
Combine this with how Watson is painted on the road (the same way as other pro Tour riders have their names painted), how people are looking up, and the dust from the takeoff.
I'd say it's real.
Why would they release the photo? To create a buzz for the next NWD, and to dispel rumours that the jump was a hoax, so as to not dissuade people from buying the video (as there is probably some people out there who would buy it for just that stunt alone).
Why is it such bad quality? To prevent the photo from being used without their permission for various things - same concept they do for MP3's on music store sites. Just enough quality for you to know what you're listening to, but not much good for anything else.
Was that really long and boring?