How to use HTML tags in element Popover component for Vue.js?

I am using Element Popover component (https://element.eleme.io/#/en-US/component/popover) with Vue.js. The popover is working and I am able to display text content.

<el-popover
    placement="bottom"
    title="Title"
    width="200"
    trigger="click"
    content="this is content, this is content, this is content"
    >
    <el-button type="primary" slot="reference" circle style="background-color:white;border-color:white" >
    <img src="img/if_Help_1493288.png" alt="Help" height="42" width="42">
    </el-button>
 </el-popover>

Is it possible to show regular html elements, e.g. <br>, <strong> or <img> in the popover content?

As mentioned in attributes description of popover component - content be passed through content prop as string or as a default slot.

So any content will be passed as a default slot, if no slot name is specified. Here is an example for your case:

<el-popover
  placement="bottom"
  title="Title"
  width="200"
  trigger="click"
>
  <el-button type="primary" slot="reference" circle style="background-color:white;border-color:white" >
    <img src="img/if_Help_1493288.png" alt="Help" height="42" width="42">
  </el-button>
  <div>
    this is content, <br> <strong>this is content</strong>, <br> this is content
  </div>
</el-popover>

Note that content prop will be replaced with content of default slot if it is passed. Can't use them both at the same time.