Back in November, Google began testing an image carousel in the featured snippets section. Well, it seems like it might be live in Google search. I see it, as do tons of others of searchers.
Here is what it looks like:
Then hover your mouse cursor over the images and you can see the arrow show up at the right image:
Then as you click and it reaches the end of the images, you have a "view all" button:
Several people are noticing this on Twitter including @azarchick, @type_SEO, @brodieseo, @MChuckGreen and more.