Image blocking is when an email client prevents images from loading automatically, often requiring the recipient to click to display them. This behavior is common in many inboxes and is influenced by privacy settings, security policies, and client defaults.
Why Clients Block Images
Images can be used for tracking and can introduce security risks, so clients may block them to protect users. Image blocking is also related to performance, because large images slow down the experience on mobile networks. When images are blocked, the email should still make sense through structure, headings, and alt text.
Designing for Image-Blocked Views
Use meaningful headings and spacing so the structure remains clear without imagery. Keep logos and decorative elements lightweight, but never rely on a hero image to communicate the only message. If an image contains critical text, duplicate the key phrase in real HTML text nearby.
A resilient email works even when images do not load. Use real text for key messages, keep your hierarchy clear, and ensure buttons are built as HTML rather than image-only elements. Optimize images so that when they do load, they load quickly, using image optimization and image compression techniques.
Measuring the Impact
Some audiences, such as enterprise recipients, are more likely to have strict image policies. If you serve those users, design and test for image blocking as a default, not an edge case. This also improves resilience for slow networks and older devices.
Even if users eventually load images, blocked-image first impressions matter. Slow or heavy emails can harm engagement. Monitoring email load time and testing a blocked-image view helps you catch issues before they affect customers.
Image Blocking and Topol
Topol helps teams design emails that remain usable with image blocking enabled by supporting strong structure, accessible content, and efficient image workflows. Learn more at Topol or create an account at Topol signup.