function previous()
{
  if (i==1)
  {
    i=imax
  } else
  {
    i--
  }
  document.getElementById('image_counter').value = istring.concat(i.toString(), " / ", imax.toString())
  document.getElementById('imageviewer').style.backgroundImage=images[i]

}

function startfilm()
{
  if (i==22)
  {
    myRef = window.open('portfolio_bd_f01.html','mywin','top=200,width=400,height=300,toolbar=0,resizable=0,location=0,status=0,menubar=0');
  }
}


function next()
{
  if (i==imax)
  {
    i=1
  } else
  {
    i++
  }
  document.getElementById('image_counter').value = istring.concat(i.toString(),  " / ", imax.toString())
  document.getElementById('imageviewer').style.backgroundImage=images[i]
}