This option is available on new seller registration or upgrade from buyer to seller. The seller can later at any time change their image harvesting preference on their Store Settings page to allow or disallow image harvesting. If a seller first allows image harvesting, then disallows it, then allows it again, no images are harvested from the time the seller disallows harvesting until the seller again allows it. But, any images already harvested during the time the seller allowed harvesting are retained in the catalog and are not deleted from the catalog.

BrickLink catalog admins have an image harvester that shows all items in the catalog that don't have an image for which there is a listing out there with an image for that item. Sellers who disallow BrickLink permission to harvest images from their listings are automatically excluded from this query.