What is the ideal image-to-text ratio?

The traditional guideline suggests 60% text to 40% images, but this "rule" is largely outdated. Modern spam filters evaluate content holistically-context, sender reputation, and engagement matter more than arbitrary ratios.

That said, image-heavy emails carry real risks: they fail when images are blocked (common default in Outlook and corporate environments), they're slower to load on mobile, and all-image emails can't be parsed for text-based filtering signals, making them look suspicious.

Design for images-off first. Your email should communicate its core message even with images blocked. Use live text for headlines and CTAs. Include meaningful alt text. If removing all images leaves a blank white box with "View in browser," you've failed. The ratio matters less than whether the email works without images.