It's not just gmail or yahoo mail. It's in every mail program,
including mail accounts through your ISPs.
However, one of the emails that I receive is from a Blogger account,
and her emails look fabulous! They include the pictures as well as
line breaks, etc. -- her emails look exactly like her Blogger posts.
She says she just used the normal feedburner setup that I used.
Soooo . . . maybe it's not about the mail, maybe it's about the feed.
Maybe Blogger just exports differently? Meaning "better"?