I was playing around with my Serene child theme and added some style to the image post format. By the way, if you have any name ideas, shoot them my way. “Serene child theme” is so bleh.
This is what the default link post type looks like, even if you have attached a featured image. You can change the body background color, but that’s it.
There’s nothing stopping you from adding a featured image to a post, no matter what the post format. Serene doesn’t show it when you use the link format, however. I decided to change that. In the update I pushed out today, I added the ability to display the featured image behind the link, as demonstrated by this post.