(trying to be optimistic)
This new picture could be a preview for our next update including new furniture, new rugs and new wallpaper.
(being pessimistic again)
It could also be a subtle hint for our Sims moving into a completely new environment, again a new game. The depicted furniture could be the first models of furniture there, not meant for our current games.
Just saying, all these pictures can be interpreted differently. Most people here and on Facebook tend to favor the first interpretation. Understandably, because my one is horrible.
Regarding the opinions saying Sims Freeplay cannot be shut down because it is so successful: it may not be an easy decision for them, it could just be for technical reasons. People ask for new features, all the time, and they cannot provide them because it may not be possible to squeeze any new features into the old code without making the app (even more) unstable. So they may have decided to start from scratch to be able to finally give people the features they wish for. Without any new features they will lose a lot of players sooner or later anyway. So they try to convince their players now to move with them to a new game.
This game would probably not start at once, perhaps next year. But they have to announce it now to make people understand they won't update our current game in the future. They could have done this even earlier and put it on hold for the release of Sims Mobile. This way the releases would be about one year apart.
EA is known for replacing successful games with new versions: Sims 4 (!) anyone?
Disclaimer: I don't have any knowledge about the content of the upcoming announcement. I am only less optimistic than most players.

I would be the happiest person of all of you if my interpretation was proven wrong.