Add via.placholder to useful websites

websites.html

@@ -47,6 +47,7 @@
 					<li><a href="https://vecta.io/nano" target="_blank" rel="noopener">vecta.io/nano</a></li>
 					<li><a href="https://tinypng.com/" target="_blank" rel="noopener">tinypng.com</a></li>
 					<li><a href="https://webaim.org/resources/contrastchecker/" target="_blank" rel="noopener">webaim.org/resources/contrastchecker/</a></li>
+					<li><a href="https://via.placeholder.com/" target="_blank" rel="noopener">via.placeholder.com</a> - <a href="https://via.placeholder.com/320x480/" target="_blank" rel="noopener">example</a></li>
 				</ul>
 			</section>