Mike Sacco thinks it could be from the (upcoming) Twilight Highlands. Other people on staff think it could be the Swamp of Sorrows or Wetlands post-Cataclysm. We won't know for sure though until Blizzard says something. (Note to Blizzard: Can you provide some lore associated with these screenshots? Or at least a few lines in a blue post telling us where they're from? Thanks! Love, The Community)
Update: Blizzard responded in a blue post! If Bornakk is being serious... woah.
Check out previous daily Cataclysm screenshots in our gallery bellow.