How do CDNs help with email image loading?

CDNs solve several challenges specific to email image delivery.

Geographic performance: Your server might be in Virginia, but recipients are worldwide. A CDN serves images from Tokyo to Japanese recipients, London to UK recipients. Reduced latency means faster rendering.

Traffic spike handling: Sending to 500,000 recipients? They might all open within hours, triggering half a million image requests. CDNs are built for this scale; single servers often aren't.

Reliability and uptime: CDNs have redundant infrastructure across multiple data centers. If one location has issues, traffic routes elsewhere. Email images remain available.

Caching optimization: CDNs cache your images at edge locations. Subsequent requests (even from different recipients in the same region) serve from cache, reducing origin server load.

Bandwidth economics: CDN bandwidth is often cheaper at scale than direct server bandwidth, especially for global distribution.

Email-specific considerations:

Gmail, Yahoo, and other providers may proxy images through their own systems, reducing some CDN benefits for those recipients

Apple MPP prefetches images, so Apple Mail users see fast loads regardless

CDNs still help for non-proxied clients and tracking pixel hosting

Set cache headers appropriately for your content update frequency