Why should I avoid using images for CTA buttons in email marketing?

Key findings

• Image blocking: A significant percentage of email clients, including Outlook, block images by default. If your CTA is an image, it may not be visible to recipients unless they manually enable image display. This directly impacts your email open rates and click-through rates.
• Accessibility issues: Image-only CTAs are inaccessible to users relying on screen readers or those with visual impairments. Without proper alt text, the purpose of the button remains unknown, leading to a poor user experience.
• Slow loading times: Images are larger files than text, which can cause emails to load slowly, especially on mobile devices or unstable internet connections. This can lead to recipients abandoning the email before seeing the CTA. As Cyberimpact notes, this is a primary reason to avoid image-only emails.
• Deliverability impact: Emails heavily reliant on images or image-only content can sometimes trigger spam filters, leading to reduced email deliverability and increased chances of landing in the spam folder.
• Inconsistent rendering: Despite appearing consistent during design, image-based buttons can render differently across various email clients and devices, leading to a fragmented user experience.

Key considerations

• Use bulletproof CTAs: These are HTML and CSS coded buttons that display correctly even when images are blocked. They provide a reliable and accessible call to action.
• Implement alt text: If you must use images, ensure all images, especially CTAs, have descriptive alt text so that recipients understand the image's purpose even if it doesn't load.
• Optimize image-to-text ratio: Maintain a healthy balance of text to images to improve deliverability and ensure content is visible even without images.
• Test across clients: Always test your emails across various email clients (e.g., Gmail, Outlook, Apple Mail) and devices to ensure consistent rendering and functionality.

Key opinions

• Engagement dip: Marketers frequently observe a drop in engagement metrics, such as click-through rates, shortly after switching to image-based CTAs.
• Hidden CTAs: A common frustration is realizing that their primary calls to action are completely invisible to recipients who have images turned off, leading to missed opportunities.
• Misconception of consistency: The belief that image buttons 'look the same in every browser' often blinds marketers to the fundamental problem of image blocking in various email clients.
• Lack of alt text: Many admit to overlooking the inclusion of descriptive alt text for image CTAs, rendering the button meaningless to a segment of their audience.
• Outlook's impact: For B2B marketers, Outlook's default image blocking poses a significant challenge, as it represents a large portion of their target audience who may not see their images.

Key considerations

• Educate stakeholders: It's vital for marketers to educate their teams and clients on the real implications of image blocking and accessibility for email campaigns.
• Prioritize functionality: While visual appeal is important, the primary function of a CTA is to drive action. Ensuring it's always visible and clickable should take precedence over static imagery.
• Adopt robust design: Embrace techniques like bulletproof buttons and clear fallback strategies to guarantee that CTAs are effective for all recipients.
• Monitor engagement: Continuously monitor engagement metrics to quickly identify and rectify issues caused by poor CTA implementation, as highlighted by VWO's insights on common CTA pitfalls.

Key opinions

• Spam filter triggers: Experts warn that emails with a high image-to-text ratio, especially those with image-only CTAs, are more likely to be flagged by spam filters, negatively impacting email deliverability.
• Reduced engagement: Without visible CTAs, the user journey is broken, leading to significantly lower click-through rates and overall campaign effectiveness.
• Accessibility mandate: From an accessibility standpoint, image-based CTAs without proper text equivalents are a major barrier for screen reader users, violating inclusive design principles.
• Client rendering inconsistencies: Experts emphasize that email clients handle images differently, making consistent rendering of image-based buttons unreliable and often leading to broken layouts.
• Alternative solutions: The consensus among experts is to use HTML and CSS to create bulletproof buttons that ensure visibility and functionality regardless of image blocking settings.

Key considerations

• Hybrid design strategy: Consider a hybrid approach where images enhance the design, but core elements like CTAs are robustly coded with text and HTML/CSS, as recommended by Email on Acid's insights.
• Fallback content: Always provide meaningful fallback text for images, especially interactive elements, to ensure comprehension even when images don't load.
• Prioritize user experience: Focus on creating an email experience that is functional and informative for all users, regardless of their email client settings or accessibility needs.
• Regular testing: Routinely test email campaigns across a wide range of environments to identify and fix any rendering or deliverability issues related to images and CTAs.

Key findings

• HTML/CSS preference: Email design documentation strongly recommends building CTAs using HTML and CSS for maximum compatibility and reliability, rather than embedding them as images.
• Image blocking default: Many email clients, by default, block images as a security and privacy measure. Documentation highlights this as a primary reason to avoid image-only content, especially for critical elements like CTAs. This directly impacts image-only email deliverability.
• Accessibility standards: Guidelines like WCAG (Web Content Accessibility Guidelines) indirectly support using text-based CTAs with appropriate markup to ensure screen readers can interpret and convey the button's purpose to users.
• Fallback content: Documentation often emphasizes the importance of providing robust fallback content, such as alt text or visible text versions, to maintain message integrity when images do not load.
• Mobile optimization: Responsive email design principles advocate for elements that scale well on mobile, which HTML/CSS buttons achieve more reliably than static image buttons.

Key considerations

• Use bulletproof buttons: Technical documentation commonly provides code examples for 'bulletproof' HTML buttons that maintain their appearance and functionality across a wide range of email clients.
• Prioritize alt attributes: If an image is used, documentation stresses the critical role of the alt attribute for describing the image content to those who cannot see it.
• Text-to-image ratio guidelines: Many best practice guides include recommendations for maintaining a healthy text-to-image ratio to improve both deliverability and readability.
• Simplicity and predictability: Documentation often advises favoring simpler, more predictable coding practices for email elements, as complex image-based solutions are prone to breakage.