function renderImageInfo(imageinfo) {
  console.log('imageinfo', imageinfo);

  var divloader = document.querySelector('#loader');
  var divoutput = document.querySelector('#output');
  divloader.style.display = "none";
  divoutput.style.display = "block";

  var divinfo = document.querySelector('#info');
  var divexif = document.querySelector('#exif');

  // Render general image data.
  var datacells = divinfo.querySelectorAll('td');
  renderCells(datacells, imageinfo);

  // If EXIF data exists, unhide the EXIF table and render.
  if (imageinfo['exif'] && !isEmpty(imageinfo['exif'])) {
    divexif.style.display = 'block';
    var exifcells = divexif.querySelectorAll('td');
    renderCells(exifcells, imageinfo['exif']);
  }
}
Called directly by the background page with information about the
image.  Outputs image data to the DOM.