Then we have to check all the later materials from WotLK and if they ever used this necropolis model in one of them or just the usual models of Naxxramas etc.
- - - Updated - - -
If this is a picture out of a cinematic, which I still believe, I'd say it's just the cinematic that plays after defeating Sylvanas, very much akin to the Tomb of Sargeras cinematic which was foreshadowing that we're going to Argus.