I've been looking for an easy way to add a featured image to my RSS-to-email, while sending only a summary of the post. This worked.
I did find the image size options a little confusing. In the drop down, it displayed more choices than small, medium, and large, and didn't really explain what the others were.
Plus, I was concerned about changing any of the sizes and then using Regenerate Thumbnails for fear that it would goof the images in my theme. And considering that regeneration is a one-way-trip and can't be undone, perhaps a warning to that effect is warranted.
I ended up doing the large setting, which by default is 1024 square. My images are not that big, but too big for the medium setting, so it made them full bleed on the email template, which worked fine.
I really liked the choices of how to position the image.
The fact that it works with only the post summary is a huge bonus.
Thanks for making the plugin Rob!