{# The cover of album `a` of tag `tag_id`, or the grey placeholder. #}
<span class="cover">{% if a.has_cover %}<img src="/tags/{{ tag_id }}/albums/{{ a.position }}/cover?v={{ (a.uri or a.artist ~ '/' ~ a.album)|urlencode }}" alt="" loading="lazy" onerror="this.remove()">{% endif %}</span>