用于将 JSON 属性值包装在另一个字符串中的正则表达式

问：

{ "url": "products/Sensors.html",
  "thumbnailUrl":"/images/icons/no_image.png",
  "translatedTitle": "sensors",
  ...
},
...

我想将值“localhost：8080”附加到以.png|jpg等结尾的属性“thumbnailUrl”

替换的值应为：

{ "url": "products/Sensors.html",
  "thumbnailUrl":"localhost:8080/images/icons/no_image.png",
  "translatedTitle": "sensors",
  ...
}