Valentin Pletzer has shared a screenshot on Twitter showing the image icons in related search boxes. When you expand them, they load up and it looks just as a featured snippet. The tech bloggers are still not sure if it is a feature or a bug.
It looks like Google is trying to combine the featured snippets with searches.
These look like that of featured snippets that can be expanded but it lies in the related search box.
See the forum discussion at Twitter.