Upload profile picture

Upload a new profile picture for the WhatsApp Business Profile. Uses Meta's resumable upload API under the hood: creates an upload session, uploads the image bytes, then updates the business profile with the resulting handle.

Provide the image either as a binary upload (multipart/form-data with file) or as a download URL (application/json with url) — with a URL we fetch the image server-side and upload the bytes for you. Meta's profile-photo API is bytes-only, so there is no direct URL passthrough. JPEG/PNG, max 5MB either way.