We’ve written a bit here about how some of the Presidential campaigns this cycle have embraced stripped down emails that don’t include a lot of images or fancy formatting. In that previous post, the focus was on how this format can make emails seem more personal, and not on the technical reasons to avoid using a lot of images. Josh Levy’s post yesterday about John McCain’s email mistakes inspired me to look at the issue from a more technical perspective.

The most compelling reason to limit the use of images in HTML emails is that tons of people are never going to see them. Some people actively turn off images. Others don’t see them because their email programs turn them off by default (Campaign Monitor has a great chart showing a breakdown). Some people work at companies that block images in emails to save bandwidth/stop porn. And yet more people are accessing email on cell phones that can’t read images. I have yet to see a percentage I trust completely, but it is estimated that somewhere between 25 and 50 percent of email users block at least some images in HTML emails. That is a lot.

Speaking anecdotally, I’m a lot less likely to see images in email than I did a year ago. At work we upgraded recently to Outlook 2007 which has images blocked by default. I never changed the setting and now follow the process of opting in to see images based on whether I trust the sender. I use Gmail for my personal email and follow the same procedure. (You really should check out that chart breaking down default settings for major email clients.)

So what to do. Stop using images altogether? Use them sparingly? Although a bit old, the useful Campaign Monitor blog provides a great guide to email design. Here are their six tips on how to send emails that actually gets to the recipient in a readable format:

1. Never use images for important content like headlines, links and any calls to action.
2. Use alt text for all images for a better experience in Gmail and always add the height and width to the image to ensure that the blank placeholder image doesn’t throw your design out.
3. Add a text-based link to a web version of your design at the top of your email.
4. Ensure your most compelling content is at the top (and preferably to the left).
5. Test your design in a preview pane, full screen and with images turned on and off before you send it.
6. Ask your subscriber to add your From address to their address book at every opportunity.

Anyone that has sent bulk emails out knows that it is a really stressful thing. Even if you do your job perfectly (no typos, valid web links, good HTML, etc.), your email is going to be garbled for at least a small percentage of people who have weird settings or are using funky email clients (Hello Lotus Notes). And those small percentage of people will inevitably complain to your boss’ best friend from high school and you’ll hear about it.

Given the high probability for mistakes, email is really a format where you need to keep things simple. If you have to use images, design the email so that it will degrade gracefully if images are turned off. The emails we design that use images typically look like an online version of letter head, with a single header image. If you keep it simple, you’ll get yelled out less for supposed mistakes and your click through rates will increase since more people will be able to actually see the content of your message.

Note: I just saw this post from Michael Whitney at Tech President that looks at the use of email by Presidential candidates and expands on Campaign Monitor’s tips. Great minds. Give it a read, as it goes into things in a bit more depth than my post.