Displaying contextually related posts below your posts in WordPress is a great way to reduce the bounce rate and increase the page views of your website. A related posts plugin also automatically creates internal links on your website which is great for WordPress SEO.
There are many related posts WordPress plugins already available in the market but most of them do not display thumbnails. Those that do display thumbnails with related posts, consume a lot of server memory, making your website very slow.
WP-Thumbie is one plugin, that is different. It is light on server resources and displays related posts with thumbnails. You can choose to display related posts with thumbnails in a horizontal styling or vertical styling. You can see the vertical styling below.
WP-Thumbie plugin has a very extensive plugin admin page using which you can configure almost anything about the output and display of the related posts with thumbnail.
You can download WP-Thumbie, the WordPress plugin to show related posts with thumbnails from the official WordPress plugin repository here.