data中的路径只会被当做普通的字符串，因此无法获取图片

data () {
    return {
      carousels: [
        "../assets/img/carousel_1.png",
        "../assets/img/carousel_2.png",
        "../assets/img/carousel_3.png",
       "../assets/img/carousel_4.png"
      ]
    }
  }

在data中的路径应写为：

data () {
    return {
      carousels: [
        require("../assets/img/carousel_1.png"),
        require("../assets/img/carousel_2.png"),
        require("../assets/img/carousel_3.png"),
        require("../assets/img/carousel_4.png")
      ]
    }
  }