How does lazy loading affect emails (hint: it doesn’t work)?

Lazy loading. The uweb technique where images load only as they scroll into view-doesn't work in email. Email clients don't support the loading="lazy" attribute or JavaScript-based lazy loading approaches. All images load (or don't load) when the email opens.

Why it fails: Email clients strip JavaScript entirely for security. The loading attribute isn't implemented in email rendering engines. Email clients load all referenced images simultaneously when images are enabled-there's no concept of "viewport" for progressive loading.

Don't try to optimize emails with lazy loading. Instead, reduce image file sizes through compression, limit the number of images, and optimize total email weight. These approaches actually work in email. Lazy loading is a web-only optimization; email has its own set of performance strategies.