Say it again... Design your email campaign to work without images! It is worth hammering this home as I see more and more groups moving away from the all text versions of newsletters. AND more emails coming from campaigns starting off with lots of links to images and clicks. (i would do some screen scrapes but you all know what I mean.
As more folks filter email in the mobile devise the problem is going to get even worse.
Lots of organizations are interested in email newsletters and fund-raising. What many people don't know is that most email programs are set by default to filter graphics from email. MIT Advertising Lab points to this article from Campaign Monitor with tips on how to design around how most people receive and read email. The first guideline is to "Design for images being turned off," and the reason for that is because "anyone using AOL, Gmail, Outlook 2003, Outlook Express and the latest versions of many ISPs email software will never see images in any emails you send them by default."