jquery实现根据浏览器窗口大小自动缩放图片的方法

(function($){
 $.fn.resizeimage = function(){
  var imgLoad = function (url, callback) {
   var img = new Image();
   img.src = url;
   if (img.complete) {
    callback(img.width, img.height);
   } else {
    img.onload = function () {
     callback(img.width, img.height);
     img.onload = null;
    };
   };
  };
  var original = {
   width:$(window).width()
  };
  return this.each(function(i,dom){
   var image = $(this);
   imgLoad(image.attr('src'),function(){
    var img = {
     width:image.width(),
     height:image.height()
    },percentage=1;
    if(img.width<original.width){
     percentage = 1;
    }else{
     percentage = (original.width)/img.width;
    }
    image.width(img.w=img.width*percentage-30).height(img.h=img.height*percentage);
    $(window).resize(function(){
     var w = $(this).width();
     percentage = w/img.width>1?1:w/img.width;
     var newWidth = img.width*percentage-30;
     var newHeight = img.height*percentage;
     image.width(newWidth).height(newHeight);
    });
   });
  });
 };
})(jQuery);