Thumbnails not appearing

This plugin is exactly what I’ve been looking for! I’m excited about adding it to all my pages but I can’t get the thumbnails to show up next to the links – like in the screenshots found on the plugin’s site.

I was not able to find anything in the settings page regarding thumbnails – am I missing something?

Thanks!

http://ww.wp.xz.cn/extend/plugins/author-recommended-posts/