The extent of shelling of Tskhenvali by Saakasvhili is not a settled matter. In one Russian (!) newspaper, Novaya Gazeta, i think, it was reported that Georgia leveled a block of govt buildings in Tskhenvali, but damage to the rest of the city was minor. A panic started and everyone hid in the basements. Lack of graphic images from Tskhenvali and later portraying images from Gori as images from Tskhenvali on Russian TV would support that assertion.

Obviously, at this point the city is completely destroyed by Russian planes, who were trying to uproot Georgians from it, and probably killed many of the people in those basements, who did not get out. And then, by subsequent Georgian shelling. It will not be known with any certainty what Georgia did in Tskhenvali, as both sides will claim that other destroyed the city. The difference being is that Russia is more likely to be believed in this specific claim, which is necessarily reflective of the actual situation.