var swatchimages = new Array;
swatchimages[1] = 'a.gif';
swatchimages[2] = 'b.gif';
swatchimages[3] = 'c.gif';
swatchimages[4] = 'd.gif';
swatchimages[5] = 'e.gif';

function changeswatch(id) {
  e = document.getElementById('sidebar');
  if (e) e.style.backgroundImage = 'url(uploads/images/'+swatchimages[id]+')';
}