{{- $thumbnailResource := .Resources.GetMatch (index .Params "thumbnail")
                        | default (index (.Resources.ByType "image") 0) -}}
{{- $orientation := partial "images/orientation_angle.html" $thumbnailResource -}}
{{- $thumbnail := $thumbnailResource.Fit (printf "%dx%d r%d" 600 600 (sub 360 $orientation)) -}}
{{- $thumbnail = $thumbnail.Crop "600x600" -}}
{{- $altText := $thumbnailResource.Params.alt -}}
<a href="{{ .RelPermalink }}" title="{{ .Title }}">
  <img src="{{ $thumbnail.RelPermalink }}" {{ with $altText }}alt="{{ . }}"{{ end }}>
</a>