jQuery image preloading implementation code for proportional scaling_jquery

/*
* Image preload and auto zoom
* scaling Whether to automatically scale in equal proportions
* width The maximum height of the image
* height The maximum width of the image
* loadpic The path of the image being loaded
* example $("*").LoadImage(true,w, h);
*/
jQuery.fn.LoadImage=function(scaling,width,height,loadpic){
if(loadpic==null)loadpic="../images/loading.gif" ;
return this.each(function(){
var t=$(this);
var src=$(this).attr("src")
var img=new Image( );
//alert("Loading...")
img.src=src;
//Auto-scaling pictures
var autoScaling=function(){
if(scaling) {
if(img.width>0 && img.height>0){
if(img.width/img.height>=width/height){
if(img.width>width){
t.width(width);
t.height((img.height*width)/img.width);
t.css("margin-top", (height-t.height( ))/2);
}else{
t.width(img.width);
t.height(img.height);
t.css("margin-top", ( height-t.height())/2);
}
}
else{
if(img.height>height){
t.height(height);
t.width((img.width*height)/img.height);
t.css("margin-top", (height-t.height())/2);
}else{
t.width(img.width);
t.height(img.height);
t.css("margin-top", (height-t.height())/2);
}
}
}
}
}
//The cached image will be automatically read when processing ff
if(img.complete){
//alert( "getToCache!");
autoScaling();
return;
}
$(this).attr("src","");
var loading=$("< ;img alt="Loading..." title="Picture loading..." src="" loadpic "" />");
t.hide();
t.after( loading);
$(img).load(function(){
autoScaling();
loading.remove();
t.attr("src",this.src);
t.show();
//alert("finally!")
});
});
}