Content template background based on existence of featured image

Hi there,

On my blog page I’d like the first post to use the post title on top of the featured image as background image. That’s easy with a GP element type content template.

Not all my posts have featured images though. In that case I’d like to use a default image instead as background for the title of the first post.

What’s the most efficient way to do that with GP (content template background image depending on if featured image exists)?

Best,
Thomas