If you're into email marketing, you've probably heard that you're not supposed to send image-only emails. Many reasons have been put forward for this. Your email will be sent to spam. Your viewers won't be able to see it. It's bad for accessibility. All of these reasons were good. But as email has advanced, the landscape has changed. Let's take a look at how the changing landscape has impacted images in emails and update some of our best practices for 2021 and beyond. I will guide you: What is Email Image Blocking Why the images are not showing Where they are disabled by default Who Would Block Images From Emails How to optimize for disabled images What is that?
Email image blocking is the practice in which images are blocked in emails or not displayed by email clients or company servers. This results in images not appearing in emails, like this one with almost no image ALT text: Blueland email with blocked E-Commerce Photo Editing Service images Email consisting of 2 images: non-descriptive limited ALT text provided Or this one with better ALT text from the image (still doesn't look great, does it?): DSW Email with Email Image Blocking Email created with multiple images: the ALT text provided is a bit more descriptive in places Why does this happen?
There are several reasons why email clients block images or disable them by default. The main reason being security. Microsoft claims to block images to help their readers avoid seeing potentially offensive content and to protect them from malicious code. They also offer the point that default image blocking allows people with lower bandwidths to choose whether they want to use that bandwidth for image downloads or not. For email clients that have images enabled by default, many of them use image proxy servers to host the images instead of having the images come directly from external hosts. This allows email clients to scan for viruses and malware before images reach inboxes, reducing the need to block images as a security feature. The bandwidth argument would still be a good reason to enable image blocking, but all of the mobile email clients we tested allow images by default. Subscribers have to really dig to find how to disable images for their mobile devices. This makes it even more important for email marketers to ensure that all images used are optimized.