The Galaxy S8 and the Galaxy S8+ feature a newer user interface with dozens of new features, and some of them are easier to overlook. One such new feature is the ability to show web link previews in the messages app.
Similar to WhatsApp, iMessage, and a few other instant messaging apps, Galaxy S8's new messages app shows a web link preview whenever someone sends you a URL, which makes it easier for you to know what that link is about.
You can disable this feature, if you don't want it, from the settings menu of the messages app.
