{ 
  "table":"all_controls",
  "layout":"form",
  "onecolumn":true,
  "caption": "Image Upload - Thumbnails",
  "fields": [
    {"name":"x_primary", "type":"int", "key":1},
    {"name":"x_image_with_thumbnails","type":"file",
      "controlparams": {
        "data_folder": "tutorials_all_controls", 
        "image": {
          "resize": [800,600],
          "format": "jpg"
        },
        "thumbnails": {
          "small": { "format": "jpg", "crop": [100, 100] },
          "medium": { "format": "jpg", "resize": [400, 400, { "upsize": true, "extend": true }] }
        }
      }
    }
  ]
}