For the last few weeks your complete look —vanity + wardrobe customizations together— has been stored each time you change it (as long as you had it for more than 5 minutes). Now, each of those looks is available to you for fast-switching from the Imagination Menu (bottom left: "Your Looks").
The changes appear both to you and to other players much quicker than they are when creating a new look from the vanity/wardrobe (because all the data is already available on the servers) but it still takes a moment to show up everywhere.
So, store your birthday suit, some spooky favorites and your Sunday best to impress your friends — your friends are easily impressed, right? You can remove any looks you don't want to keep so your list is whittled down to the best versions of each outfit.
Note: "Your Looks" has taken the place of the key ring in the imagination menu. So, the key ring is now only available from your magic rock (see "House Keys" on the Rock's menu) and the "Player Menu" (the thing you get when you click on your face; hotkey "z") . We are considering other places for this in the long run.
[Edited to add] Note 2: In the long run, this will replace the "saved outfits" feature because it is about 10x more awesome than saved outfits. If there are outfits you love in looks that have not been saved, consider giving them a wear.