| name | image-cdn |
| description | Use when reviewing image assets, markup, and CDN or build transforms related to Serve images from a CDN. Check encoded size, rendered size, loading strategy, and above-the-fold impact together. |
| metadata | {"category":"images","priority":"high","difficulty":"intermediate","estimatedTime":"30","source":"frontendchecklist.io","url":"https://frontendchecklist.io/en/rules/images/image-cdn"} |
Serve images from a CDN
Image CDNs automatically optimize, resize, and convert images on-the-fly—delivering the smallest file in the best format without manual processing.
Quick Reference
- Use image CDN for automatic format conversion (WebP, AVIF)
- Generate responsive sizes on-the-fly via URL parameters
- CDN edge caching delivers images from nearest location
- Popular options: Cloudinary, Imgix, Cloudflare Images, Vercel
Check
Verify if images are served from a CDN or image optimization service.
Fix
Configure an image CDN like Cloudinary, Imgix, or Cloudflare Images for automatic optimization.
Explain
Explain how image CDNs provide on-the-fly optimization, resizing, and format conversion.
Code Review
Review image assets, markup, and delivery configuration related to Serve images from a CDN. Flag exact files or components where format choice, sizing, or loading behavior violates the rule, and describe how to confirm the fix in DevTools.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/en/rules/images/image-cdn
