imgconfig.json

{
  "all": [
    ["rotate"],
    ["toFormat", "jpeg", { "quality": 80 }]
  ],
  "key": "%(filename)s-%(sz)s.jpg",
  "params": {
    "ACL": "public-read"
  },
  "output" : {
    "default" : {
       "outputdir": ""
    }
  },
  "operations": [
    ["resize"],
    ["max"],
    ["withoutEnlargement"]
  ]
}