{{ $mode := .Get 0 }}
{{ if eq $mode "on" }}
   <img src="{{ .Page.Site.BaseURL }}img/on-off/switch-on-icon_smal.png" alt="On">
{{ else if eq $mode "off"}}
   <img src="{{ .Page.Site.BaseURL }}img/on-off/switch-off-icon_smal.png" alt="Off">
{{ else }}
   ???
{{end}}