erynwells.me/layouts/photos/li_thumbnail_in_grid.html

{{- $thumbnail := partial "photos/thumbnail.html" (dict "Page" . "Width" 600 "Height" 600) -}}
{{- $thumbnail = $thumbnail.Crop "600x600" -}}
{{- $numberOfImages := len (partial "photos/list.html" .) -}}
{{- $hasMultipleImages := gt $numberOfImages 1 -}}
<a href="{{ .RelPermalink }}" title="{{ .Title }}" data-number-of-images="{{ $numberOfImages }}">
  {{ if $hasMultipleImages }}<div class="badge">{{ $numberOfImages }}</div>{{ end }}
  {{ range partial "photos/thumbnails.html" (dict "Page" . "Height" 600 "Width" 600)  -}}
    {{- $altText := .Params.alt -}}
    <img src="{{ .RelPermalink }}"{{ with $altText }} alt="{{ . }}"{{ end }} loading="lazy">
  {{- end }}
</a>