{
  "differing.png": {
    "new": 777777777, 
    "old": 888888888
  }, 
  "missing-from-new.png": {
    "new": null, 
    "old": 44444444
  }, 
  "missing-from-old.png": {
    "new": 3333333, 
    "old": null
  }
}