Sending a multipart message with image and text

{
  "recipient": {
    "id": "FBID"
  },
  "message": {
    "raw": {
      "multipart": [{
        "attachment": {
          "type": "image",
          "payload": {
"url":"IMAGEURL", 
        "is_reusable":false}}},
          {
"text":"test"
      }]
    }
  }
}