My RSS feed at /blog/feed only shows the title and the link for each post. I want title, link featured image and excerpt.

I am using a child theme of Salient. There is nothing in the child theme's functions file, so is something in Salient defining the RSS feed, or is this now the Wordpress standard approach in 4.7.1??

How can I fix this? Ideally, I would like my feed to look something like the attached image.

Thanks,
Larry

Edit