Person Hover Card

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "div",
  "style": {
    "display": "=if(@currentField,'','none')"
  },
  "children": [
    {
      "elmType": "img",
      "style": {
        "width": "32px",
        "min-width": "32px",
        "height": "32px",
        "overflow": "hidden",
        "border-radius": "50%",
        "margin": "2px"
      },
      "attributes": {
        "src": "=getUserImage(@currentField.email,'s')",
        "title": "@currentField.title"
      }
    },
    {
      "elmType": "span",
      "style": {
        "vertical-align": "middle",
        "margin-left": "2px"
      },
      "txtContent": "@currentField.title"
    }
  ],
  "defaultHoverField": "@currentField"
}