Unless you have a really good reason to use rich-text and graphics in your emails, don’t. Send plain text, 60-70 characters wide, just like a personal email.
Why not send a rich text email?
First, rich text is more likely to get caught in spam filters. Secondly, it LOOKS blatantly commercial, before the person even opens it. More likely to get deleted.
Third, simplest is best. If you’re doing it just to look good, don’t do it.
What are legitimate reasons for using rich text?
One reason is if pictures are a necessary part of the message. Another is for tracking purposes. You can’t tell whether a plain text email was opened or not. Rich text email gets graphics from a website and graphic files can be embedded to track how many of your emails get opened.
