Email Image-to-Text Ratio: Debunking 3 Common Myths

Email marketing has come a long way. What started as simple, text-based messages has evolved into highly visual, personalized experiences that can feature everything from dynamic product recommendations to real-time content.

But despite how much email has evolved, a few misconceptions about image-heavy emails are still hanging around.

Images hurt deliverability. Email clients block images. Image-heavy emails can’t be accessible.

So, how much of this is true, and what's outdated? We're breaking down three common myths about email image-to-text ratio, along with best practices for creating emails that look great, reach the inbox, and deliver a positive experience for every recipient.

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Myth #1: Image-heavy emails automatically hurt deliverability

For years, email marketers were encouraged to follow a specific image-to-text ratio, often 40% images and 60% text, to avoid triggering spam filters.

The reasoning was that spam filters had a hard time evaluating text embedded within images. While this was once a legitimate concern, email filtering has become much more sophisticated with the use of AI vision models.

Today, there's no universally recommended image-to-text ratio that guarantees better deliverability. Email providers evaluate a range of factors, including sender reputation, email authentication, spam complaints, sending practices, and how recipients interact with messages.

In fact, Gmail's sender requirements place significant emphasis on authentication protocols like SPF, DKIM, and DMARC, along with maintaining low spam complaint rates and making it easy for recipients to unsubscribe.

That means marketers have much more important things to focus on than hitting an arbitrary image-to-text ratio.

And what about those so-called spam trigger words?

Using promotional language doesn't automatically send an email to the spam folder. While misleading or suspicious messaging can contribute to filtering decisions, words like "sale" or "discount" aren't inherently problematic. It's also important to distinguish between an email landing in Gmail's Promotions tab and being flagged as spam. They're not the same thing.

The takeaway: Rather than worrying about the percentage of images in an email, focus on sending relevant content to people who want to receive it. Personalization can help make that content more useful and engaging, while strong sending practices help protect deliverability.

That doesn't mean marketers should build an entire email as one large image. Including meaningful HTML text, clear calls to action, and descriptive ALT text helps ensure recipients can still understand and interact with the message when images aren't displayed.

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Myth #2: Many email clients block automatic image downloads

As with the deliverability myth, the idea that most email clients block automatic image downloads doesn't tell the full story. Many popular email clients now display images by default, but there are still some exceptions worth considering.

For example, Gmail automatically displays images unless a message is considered suspicious or the recipient has changed their settings. However, Microsoft confirms that classic Outlook still blocks automatic downloads of external images by default.

Individual privacy settings, corporate security policies, and email client configurations can also affect whether images appear.

For B2B marketers, this is particularly important, as audiences may be more likely to use corporate Outlook environments with stricter security settings. B2C marketers may see different email client preferences across their audiences, so it's important to understand where and how recipients are opening emails.

The good news is that image blocking doesn't mean marketers need to avoid using images altogether. Instead, the focus should be on creating emails that provide a positive experience whether images are displayed or not.

Including descriptive ALT text, keeping essential information accessible through HTML text, and testing how emails appear with images disabled can help ensure recipients don't miss important content.

Ultimately, marketers should feel confident using image-based content while making sure their emails work across different clients, devices, and settings.

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Myth #3: Image-heavy emails can’t be accessible

Images can make emails more engaging, but what happens when someone uses a screen reader to access your content?

Screen readers can't reliably interpret information embedded within an image on their own. Without an appropriate text alternative, recipients may miss important messaging, offers, or calls to action.

Fortunately, there are ways to make image-based content more accessible.

One of the most important is ALT text, which provides a written description of an image so people using screen readers can understand its purpose.

But accessibility goes beyond adding a few descriptions.

Email marketers should also consider how content is structured, whether text has sufficient contrast against its background, and whether important information is available as live HTML text rather than exclusively within an image.

For example, if an email includes an image featuring a promotional offer, the ALT text should communicate the relevant details rather than simply describing what the image looks like. Decorative images, on the other hand, can use empty ALT attributes so screen readers can skip them.

What about personalized and real-time images?

ALT text can also be personalized using customer data. For example, an image displaying a customer's loyalty tier could include dynamic ALT text reflecting their current status, provided that information is available when the email is generated.

Real-time content can be a little trickier. If an image features information that changes after the email is sent, such as a live countdown or an API-driven chart, the ALT text may not be able to reflect the latest values.

In these cases, marketers can describe the purpose of the content and direct recipients to a web page where the most current information is available.

For example, an email featuring a real-time loyalty progress chart might use ALT text such as "View your current loyalty status and progress toward your next reward," with a link to the customer's account.

The takeaway: Image-heavy emails aren't inherently inaccessible, but they do require thoughtful design. By combining descriptive ALT text, accessible HTML, and clear content structure, marketers can create visual experiences that work for more recipients.

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The bottom line

There's no magic image-to-text ratio that guarantees better email performance.

While the old rules around image-heavy emails have evolved, the fundamentals of a good email experience haven't changed. Your content should be relevant, accessible, easy to interact with, and designed with your audience in mind.

Images can play an important role in making emails more engaging, especially when they're personalized to reflect each recipient's interests, preferences, and behaviors.

The key is making sure those experiences work for everyone, whether they're opening on mobile, using a screen reader, or viewing an email with images disabled.

Instead of designing around an arbitrary ratio, focus on creating emails that deliver value to your customers. That's a much better use of your time than counting images.