No prompt appeared at all, and the picture is black
WhyYou almost certainly answered this prompt before — probably with Block, possibly by accident, possibly months ago. Browsers remember that answer per site and do not ask twice.
FixThis is the common one, and it is not something the site can undo from its side. Open the padlock or settings icon next to the address bar, find Camera, set it back to Allow or Ask, then reload the page.