var gTrans=new Image();
gTrans.src="images/trans.gif";

var gRollImagesLoaded = false;
var gBaseDir="";
var gSingleImagesLoaded = false;
var gSingleImageDir="";
var gImgArr=new Array();

function setSrc(ob,imgName)
{
   if(gSingleImagesLoaded)
      ob.src = gImgArr[imgName].src;
}

//requires preloadRollImages to have been called
//to load roll images & set gBaseDir
function IDRoll(ob)
{
   if(gRollImagesLoaded == true)
   {
      var imgName=ob.id+"R";
      ob.src = gImgArr[imgName].src;
   }
}

function IDUnroll(ob,ext)
{
   ob.src = gBaseDir+ob.id+"."+ext;
}

function transImage(ob)
{
   ob.src = gTrans.src;
}

function preloadRollImages()
{
   var args=preloadRollImages.arguments;
   gBaseDir=args[0];
   rollDir=args[1];
   var ext=args[2];
   var x;
   var imgName;
   for(i=3; i < args.length; i++)
   {
      x=args[i];
      imgName=x+"R";
      gImgArr[imgName]=new Image();
      gImgArr[imgName].src=rollDir+x+"."+ext;
   }
   gRollImagesLoaded=true;
}

function preloadSingleImages()
{
   var args=preloadSingleImages.arguments;
   gSingleImageDir=args[0];
   var ext=args[1];
   var imgName;
   for(i=2; i < args.length; i++)
   {
      imgName=args[i];
      gImgArr[imgName]=new Image();
      gImgArr[imgName].src=gSingleImageDir+imgName+"."+ext;
   }
   gSingleImagesLoaded=true;
}