This photo really does look like a Pyxicephalus adspersus with P. edulis colour:
I think Will is taking the easy way out with this obbianus business - I think there are probably several species within the Pyxicephalus genus but no on has done any work to find out. From what we've seen over the years, it's at least safe to say there is more than one subspecies of Pyxicephalus adspersus.