Hold on, how is "hero" a food metaphor? I mean, I understand that there are some regional dialects that use that name for a "submarine" sandwich (and there are many other names for it), but I can't fathom how a full-screen image at the top of a website has any metaphorical connection to that. To me, that makes even less sense than the idea that such an image somehow is supposed to do a heroic job of advocating for whatever is the main point of the page (unironically my prior mental model!).