public function icon(Fact $fact): string
    {
        $asset = 'public/css/' . $this->name() . '/images/facts/' . $fact->getTag() . '.png';
        if (file_exists(Webtrees::ROOT_DIR . 'public' . $asset)) {
            return '<img src="' . e(asset($asset)) . '" title="' . GedcomTag::getLabel($fact->getTag()) . '">';
        }

        // Spacer image - for alignment - until we move to a sprite.
        $asset = 'public/css/' . $this->name() . '/images/facts/NULL.png';
        if (file_exists(Webtrees::ROOT_DIR . 'public' . $asset)) {
            return '<img src="' . e(asset($asset)) . '">';
        }

        return '';
    }