:wrench: Fallback to icon when main image is not available

src/templates/main.html

@@ -77,6 +77,8 @@ $if(title)$
                 <h1 class="title">$title$</h1>
 $if(img.main)$
                 <img class="rounded" src="$img.main.path$"$if(img.main.alt)$ alt="$img.main.alt$"$endif$>
+$elseif(img.icon)$
+                <img class="rounded" src="$img.icon.path$"$if(img.icon.alt)$ alt="$img.icon.alt$"$endif$>
 $endif$
 $if(subtitle)$
                 <h2 class="subtitle">$subtitle$</h2>