Imagine starting class without saying anything. The students look at you, awaiting something. You wait long enough to catch their attention, and then project this image in front of them:
|Image source: Rushton Hurley https://www.instagram.com/p/BOIHTiEFzz4/|
You then speak up, asking the class to take a close look at the sculpture, and in pairs, come up with at least three connections between what they see and what was covered in the last class. Let them know that truly cool answers earn style points, which aren't factored into their grades, but are a good thing to have earned, anyway.
It's not that your last class is expected to have covered Tang Dynasty sculpture. In fact, the idea is that you didn't. What you want is for the students to actively talk with each other about what you covered last without your having to say, "Okay class, let's review what we covered yesterday."
In other words, make learning a little more active, a little more creative, and a little more fun with an image. Any image that doesn't get you fired is probably okay. Hopefully they'll come up with some cool connections!