dcumberland on "Adding featured image to custom RSS feed"

I'm working on setting up a custom RSS feed so that I can offer a nice & clean weekly summery of my blog to my readers via Mailchimp.

I followed these instructions by Yoast to set up a custom feed. My feed is working great and looks great in Mailchimp, BUT I would like to add the featured images to it.

Here's my custom feed.

I would prefer not to alter the way other RSS feeds look on my site, as I have some readers using them and I use them for other Mailchimp purposes. Is there a simple way to do this?

Thanks in advance!

ps- I don't know a ton of code, but I know enough to get myself this far ;-)