Jackson Lo shared a video-cast of a set of Google Shopping Ads that shows the product image change and rotate to a new product image when you hover your mouse over the image. He shared a video of it in action on Twitter, but here is a shorter GIF of this:

I cannot replicate this so it seems like a test.

Here is Jackson’s tweet with the full video:

I assume Google checks if a product has multiple images and then can do this product image rotation carousel or whatever they may be calling it?

Forum discussion at Twitter.

So this is not new: