Does image-to-text ratio still impact email deliverability directly?

While not as critical as before, a balanced image-to-text ratio can still contribute positively to overall email health. It's less about a strict rule and more about creating a good user experience that supports higher engagement and, in turn, a better sender reputation.

How important is alt text for images in emails?

Alt text is crucial for accessibility. It provides a text description of your images for screen readers and also displays when images are blocked by email clients. This ensures your message is conveyed to all recipients, improving user experience and potentially boosting engagement metrics.

What are the risks of sending image-only emails?

Sending image-only emails can lead to several problems: your message may not be seen if images are blocked, it reduces accessibility for users with screen readers, and it can increase email loading times. While it may not instantly trigger blocklist (or blacklist) placement , it can indirectly harm your sender reputation through poor engagement.

What are the best practices for using images in emails?

Focus on optimizing image file sizes to ensure fast loading times. Always use descriptive alt text. Ensure your email has a clear, text-based fallback (a plain text version ) for accessibility. Most importantly, build a strong sender reputation through consistent authentication and high recipient engagement.

Is there an ideal image-to-text ratio I should aim for?

The general recommendation has shifted from strict ratios to a more balanced approach that prioritizes user experience and accessibility. While some old guidelines suggested a 60/40 text-to-image ratio or even 80/20, there's no fixed optimal ratio in modern email marketing. Focus on conveying your message effectively, regardless of the exact ratio, as long as content is accessible.

Is image-to-text ratio still important for email deliverability? - Content - Email deliverability - Knowledge base

For years, the advice about email deliverability often included a strict guideline: maintain a specific image-to-text ratio, typically something like 60/40 or 80/20, to avoid the spam folder. The idea was that emails with too many images and too little text looked suspicious to spam filters, potentially indicating a spammer trying to hide malicious content. This conventional wisdom became a foundational rule for many email marketers. Yet, as email technology and spam filtering mechanisms have evolved, the landscape has changed. We are seeing more legitimate, image-heavy emails land in inboxes, raising questions about whether this old rule still holds true.

The focus has largely shifted from static content ratios to more dynamic indicators of sender trustworthiness and recipient engagement. Today, a sophisticated array of factors determines whether your emails reach the inbox or get sent to the spam or junk folder. This includes your sender reputation, email authentication (like SPF, DKIM, and DMARC), and how recipients interact with your messages. While the image-to-text ratio might still be a minor consideration for some legacy spam filters, it's rarely the primary reason for deliverability issues anymore. It is still something to consider in the broader context of your email strategy.

The evolving role of image-to-text ratio in deliverability

Modern email deliverability is primarily driven by sender reputation. Internet Service Providers (ISPs) and mailbox providers like

Gmail and

Yahoo have highly sophisticated algorithms that analyze a multitude of signals beyond just content. These signals include your domain's sending history, bounce rates, spam complaint rates, and engagement metrics such as opens and clicks. If your sender reputation is strong, you have more leeway with your email content, including the image-to-text balance. Large, reputable brands often send image-heavy emails or even image-only emails without facing deliverability issues, precisely because their overall sender reputation is high.

While some older anti-spam filters may still consider content ratios, their impact is significantly diminished. These systems, such as SpamAssassin, might assign a higher spam score to image-heavy emails. However, major mailbox providers integrate this into a much larger, more complex scoring system where content weight is often outweighed by behavioral and historical data. Think of it as one small ingredient in a very large recipe; it might add a subtle flavor, but it won't ruin the whole dish if other ingredients are perfect.

Ultimately, the impact of image-to-text ratio on email deliverability has become more nuanced. While strict adherence to an arbitrary ratio is no longer a golden rule, understanding the potential implications of an image-heavy design remains important. This is less about tricking spam filters and more about providing a positive experience for your recipients, which in turn boosts engagement and strengthens your sender reputation.

Why image-heavy emails can still be problematic

Despite the reduced emphasis on image-to-text ratio for spam filtering, there are still compelling reasons to avoid sending image-only emails or those with very minimal text. The primary concern here shifts from strict deliverability rules to user experience and accessibility. Many email clients block images by default, meaning that if your email is just one large image, recipients will see nothing but a blank space or a broken image icon unless they choose to enable images. This creates a poor user experience and can lead to immediate deletions, low engagement, and potentially spam complaints, all of which negatively impact your sender reputation.

Accessibility is another critical factor. Users who rely on screen readers will not be able to understand your message if it's primarily image-based and lacks proper alt text. Voice assistants like

Alexa can read your emails, but they generally only read the text content, ignoring images unless they have proper alternative text. This highlights that a well-balanced email design with sufficient text ensures your message is accessible to all users, regardless of their email client settings or assistive technologies. Ignoring accessibility can lead to a significant portion of your audience missing your message entirely.

Finally, large image files can impact loading times, especially on slower internet connections or mobile devices. This contributes to a negative user experience and can cause recipients to abandon your email before it fully loads. Optimized images and managing email image sizes are more important than the ratio itself. While images alone may not directly impact deliverability, the resulting poor user experience can indirectly lead to lower engagement metrics, which in turn affects your sender reputation and inbox placement over time.

Best practices for images in emails

Instead of focusing on a rigid image-to-text ratio, adopt best practices that prioritize both deliverability and user experience. This means ensuring your emails are engaging, accessible, and technically sound. A good rule of thumb is to ensure that your message remains clear and understandable even if images do not load. This approach aligns with modern spam filtering, which prioritizes user engagement and authentication over archaic content-based rules.

Old rule focus

Historically, the main concern was avoiding spam filters that looked for image-heavy emails as a sign of malicious intent. This led to strict adherence to ratios like 60% text to 40% images (or less). Filters were simpler, and content scrutiny was high.

Spam filtering: Primarily based on content analysis, with heavy weighting on image-to-text ratio and hidden links within images.
Design limitations: Designers were often constrained by the need to include a significant amount of visible text.

Modern deliverability focus

Today, sender reputation is the overriding factor. ISPs use complex algorithms that analyze engagement, authentication, and historical sending behavior. Content is still assessed, but it is less about a single ratio and more about overall quality and relevance to the recipient.

Deliverability: Driven by sender reputation, engagement (opens, clicks), and authentication protocols like DMARC.
Accessibility: Alt text and responsive design are critical for ensuring content is available even if images are blocked or for users with screen readers.

Here are some key considerations for using images in your emails effectively:

Always use alt text: Provide descriptive alt text for all images. This ensures your message is conveyed even when images are blocked, and it's vital for accessibility, especially for screen readers. Think of alt text as a fallback for your visual content.
Optimize image file sizes: Large images can increase overall email size, leading to slower loading times. Keep images optimized for web, compressing them without sacrificing quality. Aim to keep the total email size under 100-200KB to avoid issues.
Ensure text fallback: Design your emails so that the core message is conveyed through plain text, even if images are disabled. This often involves using a plain text version that mirrors the HTML content.
Balance content: While no strict ratio is necessary, a balanced approach combining images with sufficient text is generally a good practice. This enhances readability and caters to diverse recipient preferences.

Here's a basic example of how to ensure accessibility with alt text for an image within an HTML email:

Example of HTML image tag with alt texthtml

<img src="https://example.com/logo.png" alt="Your company logo" width="200" height="100" style="display:block;" border="0">

Views from the trenches

Best practices

Prioritize sender reputation and consistent engagement for better inbox placement, as this outweighs content ratios.

Always include meaningful alt text for images to enhance accessibility and provide context if images fail to load.

Ensure a robust plain-text alternative for your HTML emails to guarantee readability across all email clients and devices.

Optimize image file sizes to prevent slow loading times and large email file sizes that might deter recipients.

Common pitfalls

Relying solely on images to convey your message, which risks unreadability if images are blocked.

Neglecting alt text, making emails inaccessible to screen readers and visually impaired users.

Sending emails with excessively large image files, causing slow load times and potential filtering issues.

Obsessing over outdated image-to-text ratios instead of focusing on overall email quality and recipient engagement.

Expert tips

Focus on delivering content that your audience wants and expects, as high engagement can mitigate content-based filtering.

Utilize modern email authentication standards (SPF, DKIM, DMARC) to build and maintain a strong sending reputation.

Regularly monitor your email deliverability metrics, including open rates, click-through rates, and spam complaints, to identify and address issues promptly.

Consider how voice assistants interact with your emails, emphasizing text-based content for better compatibility.

Marketer view

Marketer from Email Geeks says that for accessibility's sake, alt-tags should always be filled and relevant. The text/images ratio isn't truly a deliverability criterion, though some antispam filters might still suggest it is.

2019-10-09 - Email Geeks

Marketer view

Marketer from Email Geeks says that text/image ratio may still matter to some content-based filters, but it is almost always outweighed by sender reputation.

2019-10-09 - Email Geeks

The balance in email design

In conclusion, the direct importance of a strict image-to-text ratio for email deliverability has diminished significantly. Modern spam filters are far more sophisticated, focusing heavily on sender reputation, engagement metrics, and authentication. While you no longer need to adhere rigidly to an arbitrary ratio, completely image-only emails (those with high image to text ratios) are still generally ill-advised due to concerns around accessibility, user experience, and the potential for content blocking.

The key is to create emails that provide value, are easy to consume, and are accessible to all your recipients. Prioritize using descriptive alt text, optimizing image file sizes, and ensuring your core message is conveyed through text. By focusing on these broader aspects of email deliverability and user experience, you'll naturally achieve better inbox placement and stronger engagement, regardless of a precise image-to-text ratio.