Currently, some native Confluence blueprint are using a cover image in the preview panel, such as:

• File List
• Project Task report
• Task report

However it seems like this method is not available publicly from Connect's blueprints module.

It'll be great if custom blueprint can set a custom cover image.

Related article: https://community.developer.atlassian.com/t/configuring-a-custom-image-cover-as-preview-in-connects-blueprints-module/53767