upload_image
Upload base64-encoded images to Substack's CDN to get hosted URLs for use in posts and drafts.
Instructions
Upload a base64-encoded image to Substack's CDN. Returns the hosted image URL.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| image_base64 | Yes | Base64-encoded image with data URI prefix (e.g., "data:image/png;base64,...") |