git:20260529.7c05904 to git:20261004.4b0ddb9

---

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

---

# 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.

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For full implementation details, code examples, and framework-specific guidance,

see `references/rule.md`.