This plugin enables "link previews" within WordPress posts by showing a popup thumbnail of the destination website.
This plugin will allow you to automatically show previews of external websites when a user hovers over a link in your posts. It's designed to work "out-of-the-box" and no changes should be needed on your part to make it work. However, if you are familiar with CSS, you can apply "link previews" to links in other places in WordPress site by specifying any CSS selector that you want.
A free or paid Web Shrinker account is required as you will need a service API key.