hugo-theme-wondermod/layouts/partials/cover.html

{{- with .cxt}} {{/* Apply proper context from dict */}}
{{- if (and .Params.cover.image (not $.isHidden)) }}
{{- $alt := (.Params.cover.alt | default .Params.cover.caption | plainify) }}
<figure class="entry-cover">
    {{- $addLink := (and .Site.Params.cover.linkFullImages (not $.IsHome)) }}
    {{- $cover := (.Page.Resources.ByType "image").GetMatch (printf "*%s*" (.Params.cover.image)) }}
    {{- if $cover -}}{{/* i.e it is present in page bundle */}}
        {{- if $addLink }}<a href="{{ (path.Join .RelPermalink .Params.cover.image) | absURL }}" target="_blank"
            rel="noopener noreferrer">{{ end -}}
        {{- $sizes := (slice "360" "480" "720" "1080" "1500") }}
        {{- $processableFormats := (slice "jpg" "jpeg" "png" "tif" "bmp" "gif") }}
        {{- $prod := (hugo.IsProduction | or (eq .Site.Params.env "production")) }}
        {{- if (and (in $processableFormats $cover.MediaType.SubType) (ne .Site.Params.cover.responsiveImages false) (eq $prod true)) }}
        <img loading="lazy" srcset="{{- range $size := $sizes -}}
                        {{- if (ge $cover.Width $size) -}}
                        {{ printf "%s %s" (($cover.Resize (printf "%sx" $size)).Permalink) (printf "%sw ," $size) -}}
                        {{ end }}
                    {{- end -}}{{$cover.Permalink }} {{printf "%dw" ($cover.Width)}}"
            sizes="(min-width: 768px) 720px, 100vw" src="{{ $cover.Permalink }}" alt="{{ $alt }}" />
        {{- else }}{{/* Unprocessable image or responsive images disabled */}}
        <img loading="lazy" src="{{ (path.Join .RelPermalink .Params.cover.image) | absURL }}" alt="{{ $alt }}">
        {{- end }}
    {{- else }}{{/* For absolute urls and external links, no img processing here */}}
        {{- if $addLink }}<a href="{{ (.Params.cover.image) | absURL }}" target="_blank"
            rel="noopener noreferrer">{{ end -}}
            <img loading="lazy" src="{{ (.Params.cover.image) | absURL }}" alt="{{ $alt }}">
    {{- end }}
    {{- if $addLink }}</a>{{ end -}}
    {{/*  Display Caption  */}}
    {{- if not $.IsHome }}
        {{ with .Params.cover.caption }}<p>{{ . | markdownify }}</p>{{- end }}
    {{- end }}
</figure>
{{- end }}{{/* End image */}}
{{- end -}}{{/* End context */}}