var active_pic=0;
function changePicture(dir,site,id,lang) {
  if (active_pic != id) {
    if (site == 'lage' && id == 0) {
      document.getElementById('picture_gr').src=dir+'/images/'+site+'_g_'+id+'_'+lang+'.jpg';
    } else {
      document.getElementById('picture_gr').src=dir+'/images/'+site+'_g_'+id+'.jpg';
    }
    document.getElementById('picture_kl_'+id).src=dir+'/images/'+site+'_k_a_'+id+'.jpg';
    document.getElementById('picture_kl_'+active_pic).src=dir+'/images/'+site+'_k_b_'+active_pic+'.jpg';
    active_pic=id;
  }
}