{{- $thumbnailResource := .Resources.GetMatch (index .Page.Params "thumbnail")
                        | default (index (.Page.Resources.ByType "image") 0) -}}
{{- if not $thumbnailResource -}}
    {{- errorf "No thumbnail available for %s" .Page.Permalink }}
{{- end -}}
{{- $orientation := partial "images/orientation_angle.html" $thumbnailResource -}}
{{- $thumbnail := $thumbnailResource.Fit (printf "%dx%d r%d" .Width .Height (sub 360 $orientation)) -}}
{{ return $thumbnail }}