Custom Wordpress RSS Layout

I am currently automatically e-mailing all of the posts from my blog via Mailchimp. Unfortunately, after updating my blog layout, the post images break my e-mail layout. (The new post images are too large for my e-mail layout) Mailchimp has instructions for resizing images here: <[login to view URL]> The deliverable for this project would be a RSS layout (almost identical to [login to view URL] in a standard copy of Wordpress) but would use media:content to dictate the size of images. I would use the Feed Wrangler plugin (<[login to view URL]>) for Wordpress to implement the new RSS template file.