Pay $0.01 USDC to get an upload token (recommended for images over a few KB). No request body needed. Use the returned token to upload via: curl -X POST https://img402.dev/api/upload -H 'X-Upload-Token: TOKEN' -F image=@file.png — The upload returns {url, id, contentType, sizeBytes, expiresAt}. Supports PNG, JPEG, GIF, WebP up to 5MB. 1-year retention.