function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

var currentimg='';
var buttons = new Array( 'overview_b', 'map_b', 'reports_b', 'search_b' );

function resetimages(highlight)
{
  var i = 0;
  for (i=0; buttons[i]; i++)
  {
    var target = document.getElementById(buttons[i]);
    if (buttons[i] == currentimg || buttons[i] == highlight)
    {
      target.src='buttons/' + buttons[i] + '_f2.jpg';
    }
    else
    {
      target.src='buttons/' + buttons[i] + '.jpg';
    }
  }
}

function setImg(imgid)
{
  currentimg = imgid;
  resetimages('');
}