use large image if possible

themes/hugo-sustain/layouts/partials/head.html

@@ -41,7 +41,7 @@
     <meta property="og:description" content="{{ .Summary | truncate 200 }}"/>
 
     {{ "<!-- Twitter meta-data -->" | safeHTML }}
-    <meta name="twitter:card" content="summary"/>
+    <meta name="twitter:card" content="summary_large_image"/>
     <meta name="twitter:site" content="@{{ .Site.Params.social.twitter }}"/>
     <meta name="twitter:title" content="{{ $title }}"/>
     <meta name="twitter:description" content="{{ .Summary | truncate 200 }}"/>