the following code, added several times the default picture is not added, how to add the default picture? Then replace the default image
when the picture is loaded. <el-table-column label="" width="100%" >
<template slot-scope="scope">
<el-popover
placement="right"
title=""
trigger="hover">
<img :src="scope.row.cover" width="180px" height="250px" > //
<img slot="reference" :src="scope.row.cover" style="height: 80%"> //
</el-popover>
</template>
</el-table-column>