Well, I am using RSS posts to e-mail. However, to get the feed the exact length I want, I’m manually copying the html portion of everything before the “Read More” to an excerpt. That way, the entire excerpt ends up on the e-mail.
When I do this, it copies the image size in the post. I just don’t want a bunch of extra steps to make it look right in gmail. I also don’t want a bunch of resized images on the server slowing the site down. But it’s not worth putting lower quality images on the site…