function MDown(picimage)
{
Picture_Down = eval(picimage +"D.src")
document[picimage].src = Picture_Down
}

function MUp(picimage)
{
Picture_Up = eval(picimage +"U.src")
document[picimage].src = Picture_Up
}

var backD = new Image();backD.src = "images/BackD.png";
var backU = new Image();backU.src = "images/BackU.png";
var nextD = new Image();nextD.src = "images/NextD.png";
var nextU = new Image();nextU.src = "images/NextU.png";