A simple example of the function of maintaining the scale and position of the image window is resized.

scaleKepper.js

var scaleKepper = function(e){
    var obj = $(/*selector*/)[0],
        windowWidth = $(window).innerWidth(),
        windowHeight = $(window).innerHeight(),
        aspect = obj.clientWidth/obj.clientHeight,
        result = windowWidth/aspect > windowHeight ?
            'width:'+windowWidth+"px;height:"+windowWidth/aspect+"px;margin-top:-"+((obj.clientHeight-windowHeight)/2)+"px;" :
            'width:'+windowHeight*aspect+'px;height:'+windowHeight+'px;margin-left:-'+((obj.clientWidth-windowWidth)/2)+'px';
        obj.setAttribute('style', result);
};