Turn on lazy images for testing

templates/404.html

@@ -4,7 +4,7 @@
 {%- set rel_attributes = macros_rel_attributes::rel_attributes() | trim -%}
 <picture>
 	<source srcset="{{ get_url(path='404.png') }}" media="(prefers-reduced-motion: reduce)"></source>
-	<img id="not-found" class="pixels transparent no-hover" alt="404" src="{{ get_url(path='404.gif') }}">
+	<img id="not-found" class="pixels transparent no-hover" alt="404" {%- if config.markdown.lazy_async_image -%}decoding="async" loading="lazy"{%- endif -%} src="{{ get_url(path='404.gif') }}">
 </picture>
 
 <h1>Page Not Found</h1>