If it were a real photograph, the point of view suggests that it would have to have been taken by someone doing a free-flight in a MMU. I doubt they'd do that. Some of NASA's "computer generated representations" are rather good
E.g. see
http://spaceflight.nasa.gov/gallery/images/shuttle/sts-104/html/jsc2001e19791.html
Truss S0 is missing, so it has to be before STS-110 / assembly flight 8A. (see
http://spaceflight.nasa.gov/station/assembly/flights/8a.html)
The point of view
might hide the airlock, so it
might be STS-104/7A or later, but I don't think so. See
http://spaceflight.nasa.gov/gallery/images/shuttle/sts-104/html/sts104-723-014.html. It's rather large.
The station's robotic arm is in place, so I'd guess it's supposed to be STS-100/6A (flown by Endeavour), which installed it.
The Celestia ISS model doesn't seem to have the robotic arm (I think it's too big to fold up out of sight) so it would seem to correspond to either STS-102/5A.1 (resupply, flown by Discovery) or STS-98/5A (which installed the Destiny Lab Module that's just above the shuttle, flown by Atlantis).
Correction added later:
After examining the pictures on Orion's Web site, it seems that the tiny pipe-thing is indeed supposed to be the robotic arm, so I do think your representation is appropriate for STS-100/6A. My personal opinion is that the model element being used for the arm is way too small, though.
(I haven't found a NASA picture on the Web yet which directly corresponds to the one you have.)
Does this help?
