In a post at the Emma blog, Jim Hitch tells the story of two emails he received within 20 minutes of each other. “They’re similar at first glance,” he says. “Almost identical, really. Both are very image-heavy, both came from brand-name clothing retailers, both include simple calls to action, both drive traffic to an online store, on and on I could go.”

So, what set these twins apart? Hitch discovered a key difference  when he took a look “under the hood” to see how each handled blocked images. Here’s what he found:

One email displayed only the small blue boxes that indicate an image hasn’t loaded.
The other added text that echoed the message each blocked image contained.

“That backup plan is known to the html-savvy as the alt tag,” he says, “the alternate text that shows when the images don’t load.” Because of this, the second email was still able to tout free shipping and invite subscribers to apply for a credit card.

According to Hitch, since many email programs block images by default, an alt tag workaround insures that recipients still get the gist of your message—making them more likely to enable images or click through to explore your offer.

Tag ’em. “Next time you create a campaign,” advises Hitch, “be sure to think about your own backup plan. The general rule is to set an alt tag for all of your images.”

Source: The Emma Blog. Read the full post here