Renders the image, and always renders something. It first loads the image with no Referer, since hotlink protection (Cloudflare's is one click) refuses a cross-site referrer but lets an empty one through. It then retries through GET /api/remote/image for the hosts that refuse an empty referrer too, and ends with the ThumbnailPlaceholder. An HTTP image goes through the proxy from the first try, to avoid mixed content.