用element做轮播图，用了<a>标签包裹<img>标签会让图片不布满整个item是为什么？

Question

布满情况代码
<el-carousel :interval="3500" arrow="always" >

      <el-carousel-item  v-for="img in carouselFigures" :key="img.id">
        <a  style="cursor: pointer" target="_blank"><img :src='img.src' /> </a>
      </el-carousel-item>
</el-carousel>
![布满情况][1]

未布满情况代码

    <el-carousel :interval="3500" arrow="always" >
    <a  style="cursor: pointer" target="_blank">
      <el-carousel-item  v-for="img in carouselFigures" :key="img.id">
      <img :src='img.src' /></el-carousel-item>
    </a>
</el-carousel>