Discord is slowly adding more and more customizable features. The newest being the banner users can add to their profile.
This new profile feature is visible when a user is clicked on in a Discord server.
The only details given are the image's minimum size: 600x240.
This page has a layout image you're free to use to get more out of your profile on Discord!
The video below explains what this is all about.
Simple layout with details:
Simple layout (Transparant)