Summary
The image-to-text ratio in emails significantly impacts deliverability and user experience. A high image-to-text ratio, where images dominate over text, can trigger spam filters because spammers often use image-based emails to hide content. Email clients and ISPs analyze content, and a lack of text can hinder their ability to understand the email's purpose, leading to spam classification and negatively impacting sender reputation. This also creates accessibility issues for users who have images disabled or use screen readers. Maintaining a balanced ratio, ideally around 60% text and 40% images, ensures deliverability, accessibility, and positive user experience. Techniques like image compression, alt text implementation, and providing sufficient text content are essential to mitigate the negative impacts of a high image-to-text ratio.
Key findings
- Spam Filters: A high image-to-text ratio can trigger spam filters, leading to deliverability issues.
- Sender Reputation: Using excessive images compared to text can negatively impact sender reputation.
- Content Analysis: Email clients and ISPs analyze email content; a lack of text makes it difficult to determine the email's purpose.
- Accessibility: Image-heavy emails can be less accessible to users who have images disabled or use screen readers.
- User Experience: A lack of text and reliance on images can lead to a poor user experience if images fail to load.
Key considerations
- Balanced Ratio: Maintain a balanced image-to-text ratio, aiming for around 60% text and 40% images.
- Alt Text: Use descriptive alt text for all images to improve accessibility and help email clients understand the image's purpose.
- Image Compression: Compress images to reduce file size and improve loading times.
- Sufficient Text: Ensure sufficient text content to provide context and allow email clients to understand the email's purpose.
- Testing: Test emails across different email clients and devices to ensure proper rendering and deliverability.
What email marketers say
10 marketer opinions
Maintaining a balanced image-to-text ratio in emails is crucial for achieving optimal deliverability. Email clients and spam filters analyze email content, and a disproportionate amount of images without sufficient text can lead to emails being flagged as spam. This is because many spam filters struggle to understand the email's purpose, and spammers often use image-heavy emails to bypass text-based filters. A healthy balance helps ISPs understand the email content, ensures accessibility for recipients, and improves overall engagement.
Key opinions
- Spam Filters: ISPs and spam filters analyze email content, and a high image-to-text ratio can trigger spam filters, impacting deliverability.
- Content Understanding: Email clients need sufficient text to understand the email's purpose; too many images make it difficult for them to interpret the content.
- Accessibility: Image-heavy emails can be less accessible to recipients who have images disabled or use screen readers.
- SpamAssassin: SpamAssassin assigns spam points based on the image/text ratio, affecting overall spam score.
- Balance: A good text-to-image ratio, around 60% text and 40% images, helps avoid spam filters and improve deliverability.
Key considerations
- Alt Text: Include descriptive alt text for all images to improve accessibility and help email clients understand the image's purpose.
- Image Compression: Compress images to reduce file size without sacrificing quality to improve email loading times.
- Text Content: Ensure sufficient text content to provide context and allow email clients to understand the email's purpose effectively.
- User Experience: Consider the recipient's experience, ensuring the email is accessible and easy to understand, even with images disabled.
- Testing: Test emails across different email clients and devices to ensure proper rendering and deliverability.
Marketer view
Email marketer from EmailOnAcid suggests balancing the use of images with sufficient text. The marketer explains a higher image-to-text ratio can trigger spam filters because it makes the email harder to scan and interpret by email clients and users alike, and it can also negatively impact accessibility for visually impaired recipients.
23 Aug 2024 - EmailOnAcid
Marketer view
Email marketer from Litmus recommends using images thoughtfully and balancing them with text. Litmus responds that primarily using images can make emails less accessible and harder for spam filters to understand the email's content, also adding that including descriptive alt text helps improve accessibility and helps email clients understand the image's purpose.
3 Feb 2025 - Litmus
What the experts say
3 expert opinions
A high image-to-text ratio in emails can negatively affect both deliverability and user experience. While it may not always be a direct deliverability issue, spam filters are more likely to view emails with a disproportionately high image content as suspicious. The lack of readable text impacts accessibility for users with visual impairments or those who have images disabled. If images don't load, recipients may be unable to understand the email's content, potentially leading to frustration and spam reports, which can ultimately harm deliverability.
Key opinions
- Deliverability Risk: Spam filters may view emails with a high image-to-text ratio as suspicious, impacting deliverability.
- Accessibility Issues: Over-reliance on images negatively affects accessibility for users with visual impairments or those who have images disabled.
- User Experience: High image-to-text ratios can lead to a poor user experience, especially if images fail to load, leaving recipients unable to understand the message.
Key considerations
- Text Balance: Strive for a balance between images and text to ensure that emails are both visually appealing and easily understood.
- Alt Text: Use descriptive alt text for all images to provide context for users who cannot view them.
- Email Design: Design emails to be readable and informative even if images are not displayed, ensuring a positive user experience.
Expert view
Expert from Word to the Wise answers that overly relying on images, especially without adequate text, can negatively impact deliverability and accessibility. Spam filters might view emails with a high image-to-text ratio as suspicious, and recipients who have images turned off or use screen readers will have a poor experience.
7 Feb 2023 - Word to the Wise
Expert view
Expert from Email Geeks explains that while predominantly using images in emails is bad practice for accessibility, it's generally not a direct deliverability issue unless recipients get frustrated and mark the emails as spam.
19 Aug 2021 - Email Geeks
What the documentation says
4 technical articles
Email deliverability is affected by the image-to-text ratio, as disproportionately high image content can trigger spam filters and negatively impact sender reputation. Documentation from Spamhaus, Google Postmaster Tools, and Microsoft identifies that emails with excessive images and minimal text are often viewed as suspicious due to spammers using this technique to hide content. The lack of substantial text makes it difficult for email clients to determine the email's purpose, leading to potential spam classification and issues with proper rendering, as outlined in RFC documentation. Therefore, maintaining a balanced image-to-text ratio is crucial for ensuring emails are properly interpreted and delivered.
Key findings
- Spam Trigger: Emails with a high image-to-text ratio are often flagged as spam because spammers use images to hide text.
- Sender Reputation: Excessive use of images can negatively impact sender reputation, making emails viewed suspiciously by mailbox providers.
- Content Analysis: Email clients analyze content to determine the email's purpose, and a lack of substantial text makes this difficult, leading to spam classification.
- Formatting Standards: Emails with disproportionate image content may not adhere to expected formatting standards, causing deliverability and rendering issues.
Key considerations
- Text Sufficiency: Ensure sufficient text content to provide context and allow email clients to understand the email's purpose.
- Image Optimization: Optimize images to reduce file size and improve loading times without sacrificing quality.
- Accessibility: Use descriptive alt text for all images to provide context for users who cannot view them.
- Balanced Design: Strive for a balanced design that combines visually appealing images with informative text content.
Technical article
Documentation from Microsoft on Email Best Practices indicates that a high image-to-text ratio is a characteristic often found in spam emails. The documentation responds by stating that Microsoft's email filters are designed to identify such patterns, and emails with too many images and insufficient text may be more likely to be classified as junk.
3 Nov 2023 - Microsoft
Technical article
Documentation from Spamhaus explains that while not a direct factor, using disproportionately large images or an excessive number of images compared to text can negatively impact your sender reputation. They share that this is because spammers often use images to hide text and avoid content-based spam filters, leading mailbox providers to view such emails with suspicion.
26 Apr 2025 - Spamhaus
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