Perform function in attr() callback?

Not sure if I am doing this correctly or not.

Here is my .js:

var currentIMG;
$( '.leftMenuProductButton' ).hover(function () {

     currentIMG = $("#swapImg").attr("src");
     var swapIMG = $(this).next(".menuPopup").attr("id");

     $("#swapImg").css("opacity", 0)
                  .attr("src", productImages[swapIMG], function(){
          $("#swapImg").fadeTo("slow", 1);
     });

}, function () {
     $("#swapImg").stop().attr("src",currentIMG);   
});

What I am trying to do is Set a IMG Opacity to 0 (#swapImg), replace it's src, then fade it back in. So I am trying to fade it back in using a callback from the .attr().

If I am doing this incorrectly, can someone please explain 开发者_开发知识库a better way to do this? The reason I am trying to do it in the callback is that I need the fadeTo to only occur after the new image is fully loaded, otherwise it does a bit of a flash.

I am using jQuery 1.4, and according to http://jquery14.com/day-01/jquery-14 it appears you can do a callback in the .attr() method.

You can do this with the load event like this:

$("#swapImg").css("opacity", 0).attr("src", productImages[swapIMG])
             .one("load",function(){ //fires (only once) when loaded
                $(this).fadeIn("slow");
             }).each(function(){
                if(this.complete) //trigger load if cached in certain browsers
                  $(this).trigger("load");
             });

The fade will start after the image load event fires.

$("#swapImg").css("opacity", 0).attr("src", productImages[swapIMG])
         .on("load",function(){ //fires each time when image loaded
            $(this).fadeIn("slow");
         });

This will also properly.