title: wkhtmltopdf with full page background image
body: <p>I've got wkhtmltopdf working with a header and footer image, and everything spaced well.  But the task is to use a full page background image which looks like a sort of frame, with the page text in the center.  I thought I could place this in the header, but it doesn't work - maybe the use of a full page header doesn't make sense here.  </p>
  
  <p>(These are multi-page documents, which could be of any length).</p>
  
  <p>Any ideas of how to do this?</p>
  
  <p>Thanks in advance.</p>
  
  <p>John</p>