works maybe idk i didnt test it lol

files/templates/submission_listing.html

@@ -137,6 +137,7 @@
 				{% else %}
 					<a {% if not v or v.newtabexternal %}target="_blank"{% endif %} rel="nofollow noopener noreferrer" href="{{p.realurl(v)}}">
 						<img alt="post thumnail" loading="lazy" src="{{p.thumb_url}}" class="post-img">
+						<i class="ext-link fas fa-external-link"></i>
 					</a>
 				{% endif %}
 			</div>