function changePic(way,anzPics)
{
  anzPics  = parseInt(anzPics);
  checkPic = parseInt( document.forms['picGet'].pic.value );

  if( way == 'prev' && checkPic > 1 )
  {
    showPic = checkPic-1;
  }
  else if( way == 'prev' && checkPic == 1 )
  {
    showPic = anzPics;
  }
  else if( way == 'next' && checkPic < anzPics )
  {
    showPic = checkPic+1;
  }
  else if( way == 'next' && checkPic == anzPics )
  {
    showPic = 1;
  }

  // alles aus
  for (var i = 1; i <= anzPics; ++i)
  {
    document.getElementById('pic'+i).style.display      = "none";
  }

  // irgendetwas falsch definiert oder ueberhaupt alles doof?
  if(showPic == NaN || showPic == undefined || showPic > anzPics )
  {
    // das letzte
    showPic = checkPic;
  }

  //anzeigen
  document.getElementById('pic'+showPic).style.display      = "inline";

  // merkwert schreiben
  document.forms['picGet'].pic.value = showPic;
}