What is featured video?
Featured video is the video showing in your profile page. Your featured video’s thumbnail is like your profile picture that other members see in the chat when chatting with you. Only Bio videos can be selected as the featured video and not those under Posted or Library video sections.
To enlarge your featured video, tap the Enlarge button found at the bottom left of the thumbnail. To shrink the featured video, tap the Shrink button.
See more: How can I change my featured video?