Wikia:Manage-wikia-home-collections-sponsor-hero-image-field-label/qqq

A label next to collection's bigger image field (the big image covers all wikis images on corporate main page for some time then it fades out); in the field you put an image name.

Hero graphic is a term used in web design for a specific type of banner image. A hero graphic is large banner image, prominently placed on a web page, generally front and center.