{{- if .Page.Site.Params.BookPortableLinks -}}
{{- template "portable-image" . -}}
{{- else -}}
{{- end -}}
{{- define "portable-image" -}}
{{- $isRemote := or (in .Destination "://") (strings.HasPrefix .Destination "//") }}
{{- if not $isRemote }}
{{- $path := print .Page.File.Dir .Destination }}
{{- if strings.HasPrefix .Destination "/" }}
{{- $path = print "/static" .Destination }}
{{- end }}
{{- if not (fileExists $path) }}
{{- warnf "Image '%s' not found in '%s'" .Destination .Page.File }}
{{- end }}
{{- end }}
{{- end -}}