function randomImg(){
  var myimages=new Array()
  //specify random images below. You can have as many as you wish
  myimages[1] = "url(\"./img/OfficeBuilding01.jpg\")  no-repeat scroll center top #304878"
  myimages[2] = "url(\"./img/OfficeBuilding02.jpg\") no-repeat scroll center top #304878"
  myimages[3] = "url(\"./img/OfficeBuilding03.jpg\") no-repeat scroll center top #304878"
  myimages[4] = "url(\"./img/OfficeBuilding04.jpg\") no-repeat scroll center top #304878"
  myimages[5] = "url(\"./img/OfficeBuilding05.jpg\") no-repeat scroll center top #304878"
  myimages[6] = "url(\"./img/OfficeBuilding06.jpg\") no-repeat scroll center top #304878"
  myimages[7] = "url(\"./img/OfficeBuilding07.jpg\") no-repeat scroll center top #304878"
  myimages[8] = "url(\"./img/Building001.jpg\") no-repeat scroll center top #304878"
  myimages[9] = "url(\"./img/Building002.jpg\") no-repeat scroll center top #304878"
  
  var ry = Math.floor(Math.random() * myimages.length)

  if (ry == 0)
      ry = 1
        
  $('#leftNav .nav-img').css("background", myimages[ry]);

}