function CenterRandomImage(iFolderLvl,StrCat)
{  
   var iRandomNumber ="";
   var StartImg      ="";
   var FoldLvl       ="";
   var StrImg        ="";
   var St            ="";
   St       = new Image();
   StartImg = StrImg;
   
   switch (StrCat){
     case "center":
	       iRandomNumber = 5;
		   StrImg        = "img/acc/titre_";
		   iRandomNumber = Math.round(Math.random()*iRandomNumber)
	  break   
  }
   
   for(var i=0;i < parseInt(iFolderLvl);i++)
   {
    FoldLvl=FoldLvl+"../";
   }
   
   StartImg = FoldLvl+StrImg+iRandomNumber+'.jpg';
   St.src   = StartImg
   document.randimg.src = St.src;
}