var RollOverImage = Class.create();
RollOverImage.prototype = {
    initialize: function (img){
        this.image=$(img);
        this.originalPath = this.image.src;
        if(arguments[1]) this.setMouseOverImage(arguments[1]);
        if(arguments[2]) this.setMouseDownImage(arguments[2]);
    },
    setMouseOverImage: function (path){
        this.mouseOverImage = new Image();
        this.mouseOverImage.src = path;
        this.image.onmouseover = this.rollover.bind(this);
        this.image.onmouseout = this.reversion.bind(this);
    },
    setMouseDownImage: function (path){
        this.mouseDownImage = new Image();
        this.mouseDownImage.src = path;
        this.image.onmousedown = this.mousedown.bind(this);
        this.image.onmouseup = this.reversion.bind(this);
    },
    rollover: function (){
        this.image.src = this.mouseOverImage.src;
    },
    mousedown: function (){
        this.image.src = this.mouseDownImage.src;
    },
    reversion: function (){
        this.image.src = this.originalPath;
    }
};