Use a For loop, like this

Code:
function callJS(e:MouseEvent):void
{
	e.target.filters = [clickShadow];
	
	for (var i:uint = 0; i < list.length; i++) 
	{
		if (e.target == list[i])
		{
			ExternalInterface.call("Photo_Enlarge", "/images/Pics/Pic"+ (i + 1) +".jpg", " " );
		}
	}
}