In the past, many subscribers have had images blocked by their email client. When email campaigns are produced solely as images, that made for a pretty bad experience.

These days, most email clients show images by default, albeit sometimes via a cache. So when we think about images off, we shouldn't be looking at images being disabled, and instead we should consider that all users, particularly when mobile, will be using an internet connection that can go away at any time.

The wifi on the London Underground, for example, makes for a terrible internet experience. There is only coverage in the stations, so once a device has taken 20 seconds or so to connect, users have around 10 seconds online whilst the doors close and the train pulls out of the station. In that time, a user can, and will, access their inbox and download their email, but the connection is likely to have dropped by the time they actually open. So they'll be reading our email in an environment without images, and without the ability to click through.

Research has shown that users rarely come back to the same email campaign, so we need to ensure we still communicate our message in these challenging circumstances. London Underground wifi experience is an extremity, but these factors affect many users in milder forms. Many tablets and most laptops are wifi only, for example.

We should assume that at some point, regardless of their device and email client, every user is going to see our email campaigns without images—and we'd be well placed if we treat this experience as a baseline.

If we consider the experience for these users and build up from there, we can create robust email campaigns that provide great value for fully-capable platforms and devices, yet still communicate our core message no matter what.

So even (or perhaps especially) in the mobile email age, we can do more for our users than send all-image email campaigns.