Cloudflare Images

Cloudflare Images

Status: Production Ready ✅ | Version: 3.0.0 | Last Verified: 2025-12-27

What Is Cloudflare Images?

Two powerful features:

1. Images API: Upload, store, serve images globally
2. Image Transformations: Resize/optimize ANY image

Key benefits:

• Global CDN delivery
• Automatic WebP/AVIF conversion
• Up to 100 variants
• Direct creator upload (no API keys in frontend)
• Signed URLs for private images
• Transform any image via URL or Workers

Quick Start (5 Minutes)

1. Enable Cloudflare Images

Dashboard → Images → Enable

Get your Account ID and create API token (Cloudflare Images: Edit permission)

2. Upload Image

curl --request POST \
  --url https://api.cloudflare.com/client/v4/accounts/<ACCOUNT_ID>/images/v1 \
  --header 'Authorization: Bearer <API_TOKEN>' \
  --header 'Content-Type: multipart/form-data' \
  --form 'file=@./image.jpg'

CRITICAL: Use multipart/form-data, not JSON

3. Serve Image

<img src="https://imagedelivery.net/<ACCOUNT_HASH>/<IMAGE_ID>/public" />

4. Enable Transformations

Dashboard → Images → Transformations → Enable for zone

Transform ANY image:

<img src="/cdn-cgi/image/width=800,quality=85/uploads/photo.jpg" />

5. Transform via Workers

export default {
  async fetch(request: Request): Promise<Response> {
    return fetch("https://example.com/image.jpg", {
      cf: {
        image: {
          width: 800,
          quality: 85,
          format: "auto"  // WebP/AVIF
        }
      }
    });
  }
};

Load references/setup-guide.md for complete walkthrough.

The 3 Core Features

Feature 1: Images API (Upload & Storage)

Upload methods:

1. File upload (server-side)
2. Upload via URL (ingest from external)
3. Direct creator upload (user uploads, no API keys)

Load templates/upload-api-basic.ts for file upload example. Load references/direct-upload-complete-workflow.md for user uploads.

Feature 2: Image Transformations

Optimize ANY image (uploaded or external).

Methods:

1. URL: /cdn-cgi/image/width=800,quality=85/path/to/image.jpg
2. Workers: cf.image fetch option

Load references/transformation-options.md for all options. Load templates/transform-via-workers.ts for Workers example.

Feature 3: Variants

Predefined transformations (up to 100).

Examples:

• thumbnail: 200x200, fit=cover
• hero: 1920x1080, quality=90
• mobile: 640, quality=75

Load references/variants-guide.md for complete guide.

Critical Rules

Always Do ✅

1. Use multipart/form-data for uploads (not JSON)
2. Enable transformations for zones before using /cdn-cgi/image/
3. Use direct creator upload for user uploads (don't expose API tokens)
4. Set CORS headers for direct uploads from browser
5. Use signed URLs for private images
6. Configure variants for common sizes (avoid dynamic transformations)
7. Use format=auto for automatic WebP/AVIF
8. Handle error codes (9401, 9403, 9413, 5408)
9. Set quality=85 for optimal size/quality balance
10. Use fit=cover for consistent aspect ratios

Never Do ❌

1. Never expose API tokens in frontend code
2. Never use JSON encoding for file uploads
3. Never skip CORS configuration for direct uploads
4. Never exceed 100 variants (hard limit)
5. Never use transformations without enabling for zone
6. Never hardcode account IDs in public code
7. Never skip error handling (uploads can fail)
8. Never use quality >90 (diminishing returns)
9. Never skip image validation (size, format, dimensions)
10. Never use transformations on non-proxied requests

Top 2 Use Cases

Use Case 1: User Profile Pictures

Direct creator upload pattern for user-uploaded images:

// Backend: Generate upload URL
const response = await fetch(
  `https://api.cloudflare.com/client/v4/accounts/${ACCOUNT_ID}/images/v2/direct_upload`,
  { method: 'POST', headers: { 'Authorization': `Bearer ${API_TOKEN}` } }
);
const { result } = await response.json();
return Response.json({ uploadURL: result.uploadURL });

// Frontend: Upload file
const formData = new FormData();
formData.append('file', file);
await fetch(uploadURL, { method: 'POST', body: formData });

Load templates/direct-creator-upload-backend.ts for complete example. See examples/basic-upload/ for complete working project.

Use Case 2: Responsive Images

Responsive images with srcset for optimal performance:

<img
  srcset="
    https://imagedelivery.net/abc/xyz/width=400 400w,
    https://imagedelivery.net/abc/xyz/width=800 800w,
    https://imagedelivery.net/abc/xyz/width=1200 1200w
  "
  sizes="(max-width: 600px) 400px, (max-width: 1000px) 800px, 1200px"
  src="https://imagedelivery.net/abc/xyz/width=800"
/>

Load templates/responsive-images-srcset.html for complete example. See examples/responsive-gallery/ for complete working project.

Additional Use Cases:

• Transform Existing Images: Load references/transformation-options.md
• Private Images: Load references/signed-urls-guide.md or see examples/private-images/
• Batch Upload: Load templates/batch-upload.ts
• Framework Integration: Load references/framework-integration.md for Next.js, Remix, Astro
• Watermarking: Load references/overlays-watermarks.md and templates/overlay-watermark.ts
• Custom Domains: Load references/custom-domains.md
• Webhooks: Load references/webhooks-guide.md and templates/webhook-handler.ts

Top 2 Errors Prevented

Error 1: CORS Issues with Direct Upload

Problem: Browser blocks direct upload from your domain.

Solution: Configure CORS headers when generating upload URL:

const response = await fetch(
  `https://api.cloudflare.com/client/v4/accounts/${ACCOUNT_ID}/images/v2/direct_upload`,
  {
    method: 'POST',
    headers: { 'Authorization': `Bearer ${API_TOKEN}` },
    body: JSON.stringify({
      requireSignedURLs: false,
      metadata: { source: 'user-upload' }
    })
  }
);

Error 2: Multipart Form Data Encoding

Problem: JSON encoding fails for file uploads (must use multipart/form-data).

Solution:

// ✅ CORRECT
const formData = new FormData();
formData.append('file', file);
await fetch(uploadURL, { method: 'POST', body: formData });

// ❌ WRONG
const json = JSON.stringify({ file: base64File });

Additional Common Errors:

• Error 9401 (Transformations not enabled): Load references/top-errors.md
• Error 9403 (Invalid transformation): Load references/top-errors.md
• Error 9413 (Variant limit exceeded): Load references/top-errors.md
• Error 5408 (Upload timeout): Load references/top-errors.md
• Missing requireSignedURLs: Load references/signed-urls-guide.md

Load references/top-errors.md for all 10 errors with complete solutions.

When to Load References

Core References

Load references/setup-guide.md when:

• First-time Cloudflare Images setup
• Need step-by-step walkthrough

Load references/api-reference.md when:

• Need complete API documentation
• All endpoints and parameters

Load references/top-errors.md when:

• Encountering any error code (5408, 9401-9413)
• Troubleshooting upload/transformation issues

Upload References

Load references/direct-upload-complete-workflow.md when:

• Implementing user uploads
• Need frontend + backend example
• Configuring CORS

Load references/signed-urls-guide.md when:

• Implementing private images with access control
• Need HMAC-SHA256 signature generation

Load references/webhooks-guide.md when:

• Processing upload completion events
• Implementing webhook handlers with signature verification