function replacestring(str_normal,str_find,str_replace,int_case_insensitive)
	{
		if (arguments.length<3 || str_find=="" || str_normal=="" || typeof("".split)!="function")
			return(str_normal);
	
		//no parm means default, "case SENSITIVE"...
		if(!(int_case_insensitive))
			return(str_normal.split(str_find)).join(str_replace);
	
		str_find=str_find.toLowerCase();
	
		var rv="";
		var ix=str_normal.toLowerCase().indexOf(str_find);
		while(ix>-1)
		{
			rv+=str_normal.substring(0,ix)+str_replace;
			str_normal=str_normal.substring(ix+str_find.length);
			ix=str_normal.toLowerCase().indexOf(str_find);
		};
		return(rv+str_normal);
	};//end function replacestring

	function imageOn(i) {
		theSrc = document.images["img_"+ i].src;
		document.images["img_"+ i].src = replacestring(theSrc, '.gif', 'expanded.gif',1);
	}

	function imageOff(i) {
		theSrc = document.images["img_"+ i].src;
		document.images["img_"+ i].src = replacestring(theSrc, 'expanded.gif', '.gif',1); 
	}