hugo-theme-stack/layouts/_partials/helper/thumbnail-image.html

{{- /*
Params:
    Resource: Hugo image resource object (Optional, for processing)
    Width: Image width (Required)
    Height: Image height (Required)
    Resize: Whether to perform resize (Optional, default: false)
    Attributes: Map of HTML attributes for the <img> tag
*/ -}}

{{- $resource := .Resource -}}
{{- $width := .Width -}}
{{- $height := .Height -}}
{{- $resize := .Resize -}}
{{- $attributes := .Attributes | default dict -}}

{{- if and $resize $resource (reflect.IsImageResourceProcessable $resource) $width $height -}}
    {{/* Create thumbnail with 1x/2x descriptors */}}
    {{- $srcset := slice -}}
    {{- range (slice 1 2) -}}
        {{- $w := mul $width . -}}
        {{- $h := mul $height . -}}
        {{- if and (le $w $resource.Width) (le $h $resource.Height) -}}
            {{- $resized := $resource.Fill (printf "%dx%d" $w $h) -}}
            {{- $srcset = $srcset | append (printf "%s %dx" $resized.RelPermalink .) -}}
            
            {{- if eq . 1 -}}
                {{- $attributes = merge $attributes (dict "src" $resized.RelPermalink) -}}
            {{- end -}}
        {{- end -}}
    {{- end -}}
    
    {{- if gt (len $srcset) 0 -}}
        {{- $attributes = merge $attributes (dict "width" $width "height" $height "srcset" (delimit $srcset ", ")) -}}
    {{- end -}}
{{- end -}}

<img {{- range $k, $v := $attributes -}}
    {{- if $v -}}
        {{- printf " %s=%q" (lower $k) (printf "%v" $v) | safeHTMLAttr -}}
    {{- end -}}
{{- end -}}>