{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "div",
  "style": {
    "margin": "auto",
    "padding-top": "10px",
    "padding-bottom": "10px"
  },
  "children": [
    {
      "elmType": "a",
      "attributes": {
        "href": "[$Link]",
        "target": "_blank",
        "title": "[$Link.desc]"
      },
      "children": [
        {
          "elmType": "img",
          "attributes": {
            "src": "=getThumbnailImage(@currentField,64,64)",
            "alt": "@currentField.filename"
          },
          "style": {
            "border-radius": "6px"
          }
        }
      ]
    }
  ]
}