title: Add image in header using html-pdf node module
body: <p>I am using <a href="https://www.npmjs.com/package/html-pdf" rel="noreferrer">this</a> to convert the html to PDF.The conversions are really good.But the problem is to add header and footer in the PDF pages.In the options if i add the header text i got the result what i expected.</p>
  
  <pre><code>//Options
  
      var options = {
      "header": {
          "height": "45mm",
          "contents": "&lt;div style='text-align: center;'&gt;Author: Marc Bachmann&lt;/div&gt;" // If i add image in content it wont work
      // sample i tried 
        },
        "footer": {
          "height": "28mm",
          "contents": "&lt;span style='color: #444;'&gt;{{page}}&lt;/span&gt;/&lt;span&gt;{{pages}}&lt;/span&gt;"
        }
      }
  // Tried this in contents &lt;img src="image path" /&gt;
      var result = &lt;div class="container"&gt; HTML CONTENT&lt;/div&gt;';
  
          pdf.create(result, options).toFile(fileName + ".pdf", function(err, res) {
          if (err) {
          console.error(err);
          callback();
          }
  </code></pre>
  
  <p>Then if i add the image tag in the header(contents) option i didn't get the image in the generated PDF. Can you please give me a solution for this thanks. </p>