schema.json

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "allOf": [
    {
      "$ref": "https://raw.githubusercontent.com/jsonresume/resume-schema/v1.0.0/schema.json"
    }
  ],
  "properties": {
    "basics": {
      "type": "object",
      "additionalProperties": true,
      "properties": {
        "images": {
          "$ref": "#/$defs/images"
        }
      }
    }
  },
  "$defs": {
    "images" : {
      "type": "array",
      "description": "Multi resolution images",
      "additionalItems": false,
      "items": {
        "type": "object",
        "additionalProperties": true,
        "required": ["src", "width", "height"],
        "properties": {
          "src": {
            "type": "string",
            "description": "path to the image",
            "format": "uri-reference"

          },
          "width": {
            "type": "integer",
            "description": "Number of pixes across"
          },
          "height": {
            "type": "integer",
            "description": "Number of pixels high"
          },
          "density": {
            "type": "string"
          }
        }
      }
    }
  }
}