<el-table-column prop="title" label="标题"></el-table-column>
                <el-table-column prop="" label="封面">
                    <template slot-scope="scope">
                        <img :src="scope.row.coverImage"alt="" />
                    </template>
                </el-table-column>

主要加是：<template slot-scope="scope">
                        <img :src="scope.row.coverImage"alt="" />
                    </template>

scope.row表示当前的行对象