Image Dimensions
Keep banners between 600–650px wide (matches common email client widths) and 80–120px tall. Larger images increase load time and trigger image-blocking. Use responsive attributes (max-width: 100%) so they scale on mobile.
Alt Text
Every campaign image needs descriptive alt text. Screen reader users and recipients with images disabled will hear or see it. Example: "Register for our webinar on March 15." Avoid generic text like "banner" or "image."
Link Tracking
Use tracked URLs to measure clicks. Redirect through your analytics or marketing platform so you can attribute conversions. Avoid tracking parameters that look spammy—some filters flag long, parameter-heavy URLs.
A/B Testing
Test different creatives, copy, and CTAs. Split traffic by department or randomly. Run tests for at least 2 weeks to account for send volume variance. Document winning variants for future campaigns.
Frequency
Don't run the same banner indefinitely. Rotate campaigns every 2–4 weeks. Recipients who see the same banner on every email from your company may tune it out or find it repetitive.
Compliance
Ensure campaign content complies with advertising rules in your jurisdiction. Financial services, healthcare, and legal have specific restrictions. When in doubt, involve legal or compliance.