{{ if (index .Params 2) }}
<a href="{{ index .Params 2 }}" target="_blank">
  <img src="{{ index .Params 1 | relURL | safeURL }}" alt="{{ index .Params 0 }}" />
</a>
{{ else }}
<img src="{{ index .Params 1 | relURL | safeURL }}" alt="{{ index .Params 0 }}" />
{{ end }}