Pinterest - Customize the Cover image of your Boards
Changing the cover of a board on Pinterest is easy. The cover image is the most prominent aspect of the board as it aims to capture the attention of users. The cover image also defines the thematic of the board. When you create a board Pinterest automatically use the first Pin as cover image.
To use a pin as cover image:
Login to your profile page (web version), select the board your want to modify and click on Edit Board:
Click Change cover:
Scroll through the Pins of the Board and choose a new cover image.
Make the necessary adjustments and click on Save Changes.