3-inch Photo Button

{
  "product": { "id": "photo-button-3", "revision": 1 },
  "quantity": 5,
  "assets": [{
    "role": "artwork",
    "url": "https://cdn.example.com/orders/button-art.jpg",
    "pixel_width": 1800,
    "pixel_height": 1800
  }]
}