cloudflare-images

Cloudflare Images

Status: Production Ready ✅ Last Updated: 2025-10-26 Dependencies: Cloudflare account with Images enabled Latest Versions: Cloudflare Images API v2

Overview

Cloudflare Images provides two powerful features:

1. Images API: Upload, store, and serve images with automatic optimization and variants
2. Image Transformations: Resize, optimize, and transform any publicly accessible image

Key Benefits:

• Global CDN delivery
• Automatic WebP/AVIF conversion
• Variants for different use cases (up to 100)
• Direct creator upload (user uploads without API keys)
• Signed URLs for private images
• Transform any image via URL or Workers

Quick Start (5 Minutes)

1. Enable Cloudflare Images

Log into Cloudflare dashboard → Images → Enable for your account.

Get your Account ID and create an API token with Cloudflare Images: Edit permissions.

Why this matters:

• Account ID and API token are required for all API operations
• Images Free plan includes limited transformations

2. Upload Your First 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'

Response includes:

• id: Image ID for serving
• variants: Array of delivery URLs

CRITICAL:

• Use multipart/form-data encoding (NOT application/json)
• Image ID is automatically generated (or use custom ID)

3. Serve the Image

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

Default public variant serves the image. Replace with your own variant names.

4. Enable Image Transformations

Dashboard → Images → Transformations → Select your zone → Enable for zone

Now you can transform ANY image:

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

Why this matters:

• Works on images stored OUTSIDE Cloudflare Images
• Automatic caching on Cloudflare's global network
• No additional storage costs

5. Transform via Workers (Advanced)

export default {
  async fetch(request: Request): Promise<Response> {
    const imageURL = "https://example.com/image.jpg";

    return fetch(imageURL, {
      cf: {
        image: {
          width: 800,
          quality: 85,
          format: "auto" // WebP/AVIF for supporting browsers
        }
      }
    });
  }
};

The 3-Feature System

Feature 1: Images API (Upload & Storage)

Store images on Cloudflare's network and serve them globally.

Upload Methods:

1. File Upload - Upload files directly from your server
2. Upload via URL - Ingest images from external URLs
3. Direct Creator Upload - Generate one-time upload URLs for user uploads

Serving Options:

• Default domain: imagedelivery.net
• Custom domains: /cdn-cgi/imagedelivery/...
• Signed URLs: Private images with expiry tokens

See: templates/upload-api-basic.ts, templates/direct-creator-upload-backend.ts

Feature 2: Image Transformations

Optimize and resize ANY image (stored in Images or external).

Two Methods:

1. URL Transformations - Special URL format
2. Workers Transformations - Programmatic control via fetch

Common Transformations:

• Resize: width=800,height=600,fit=cover
• Optimize: quality=85,format=auto
• Effects: blur=10,sharpen=3
• Crop: gravity=face,zoom=0.5

See: templates/transform-via-url.ts, templates/transform-via-workers.ts

Feature 3: Variants

Predefined image sizes for different use cases.

Named Variants (up to 100):

• Create once, use everywhere
• Example: thumbnail, avatar, hero
• Consistent transformations

Flexible Variants (dynamic):

• Enable per account
• Use transformation params in URL
• Example: w=400,sharpen=3
• Cannot use with signed URLs

See: templates/variants-management.ts, references/variants-guide.md

Images API - Upload Methods

Method 1: File Upload (Basic)

curl --request POST \
  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' \
  --form 'requireSignedURLs=false' \
  --form 'metadata={"key":"value"}'

Key Options:

• file: Image file (required)
• id: Custom ID (optional, default auto-generated)
• requireSignedURLs: true for private images (default: false)
• metadata: JSON object (max 1024 bytes, not visible to end users)

Response:

{
  "result": {
    "id": "2cdc28f0-017a-49c4-9ed7-87056c83901",
    "filename": "image.jpg",
    "uploaded": "2022-01-31T16:39:28.458Z",
    "requireSignedURLs": false,
    "variants": [
      "https://imagedelivery.net/Vi7wi5KSItxGFsWRG2Us6Q/2cdc28f0.../public"
    ]
  }
}

See: templates/upload-api-basic.ts

Method 2: Upload via URL

Ingest images from external sources without downloading first.

curl --request POST \
  https://api.cloudflare.com/client/v4/accounts/{account_id}/images/v1 \
  --header "Authorization: Bearer <API_TOKEN>" \
  --form 'url=https://example.com/image.jpg' \
  --form 'metadata={"source":"external"}'

When to use:

• Migrating images from another service
• Ingesting user-provided URLs
• Backing up images from external sources

CRITICAL:

• URL must be publicly accessible or authenticated
• Supports HTTP basic auth: https://user:password@example.com/image.jpg
• Cannot use both file and url in same request

See: templates/upload-via-url.ts

Method 3: Direct Creator Upload ⭐

Generate one-time upload URLs for users to upload directly to Cloudflare (no API key exposure).

Backend Endpoint (generate upload URL):

const response = await fetch(
  `https://api.cloudflare.com/client/v4/accounts/${accountId}/images/v2/direct_upload`,
  {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${apiToken}`,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      requireSignedURLs: true,
      metadata: { userId: '12345' },
      expiry: '2025-10-26T18:00:00Z' // Optional: default 30min, max 6hr
    })
  }
);

const { uploadURL, id } = await response.json();
// Return uploadURL to frontend

Frontend Upload (HTML + JavaScript):

<form id="upload-form">
  <input type="file" id="file-input" accept="image/*" />
  <button type="submit">Upload</button>
</form>

<script>
document.getElementById('upload-form').addEventListener('submit', async (e) => {
  e.preventDefault();

  const fileInput = document.getElementById('file-input');
  const formData = new FormData();
  formData.append('file', fileInput.files[0]); // MUST be named 'file'

  const uploadURL = 'UPLOAD_URL_FROM_BACKEND'; // Get from backend

  const response = await fetch(uploadURL, {
    method: 'POST',
    body: formData // NO Content-Type header, browser sets multipart/form-data
  });

  if (response.ok) {
    console.log('Upload successful!');
  }
});
</script>

Why this matters:

• No API key exposure to browser
• Users upload directly to Cloudflare (faster, no intermediary server)
• One-time URL expires after use or timeout
• Webhooks available for upload success/failure notifications

CRITICAL CORS FIX:

• ✅ DO: Use multipart/form-data encoding (let browser set header)
• ✅ DO: Name field file (NOT image or other names)
• ✅ DO: Call /direct_upload API from backend only
• ❌ DON'T: Set Content-Type: application/json or image/jpeg
• ❌ DON'T: Call /direct_upload from browser (CORS will fail)

See: templates/direct-creator-upload-backend.ts, templates/direct-creator-upload-frontend.html, references/direct-upload-complete-workflow.md

Image Transformations

URL Transformations

Transform images using a special U