With 30 years imaging experience and a lifelong interest in aviation, in my estimation that pic is the result of some pretty bad photoshopping. Given five minutes tomorrow I could probably replicate the effects in that pic rather easily.
Firstly, the 'shock wave' is completely non-symmetrical. (i.e. shaky hand on airbrush tool via mouse/graphic pen). Secondly, it starts about one or two metres back from the nose of the 747. It is also disproportionately wide relative to the aircraft.
Those with a better grounding in physics than I might know better, but surely this would require a ridiculously high speed or some sort of very humid/dense atmosphere,
My money's on 110% fake.