Normally the timing belt should sit right in the middle of the cam gear when the motor is running.
If it doesn't, there could be several causes but you would have to take it all apart to find out.
 
From looking at your pic, the edge of the belt looks to be level with the inside edge of the cam gear, so the noise you are hearing could be caused by the inside of the belt rubbing something. (The water pump housing is very close)
But if that's what is causing the sound there should be damage visible on the inside edge of the belt if you look carefully.
 
 
 
 

The noise was from the timing belt area. so i got Toyota timing belt kit and new water pump while i'm there.
the old belt was Gate and pretty bad condition don't have history on how old it is car don 190k with service book that i cant see when it was done. so the   TENSIONER ASSY was lose and old. and that was making the rattle noise that was killing me.
if any one wants photos of the old belts and   TENSIONERS i can put them up. and below are the part number from Toyota 
1356879305
1354088381
1350588382
1350363011
1610079176

BELT, TIMING
TENSIONER ASSY, T890
IDLER SUB−ASSY, T890
IDLER SUB ASSY ST162
PUMP ASSY, WATER