Reversing this hover effect?

[mikes02]

http://www.sohtanaka.com/web-design/greyscale-hover-effect-w-css-jquery/

I want to implement this hover effect but I am getting hung up on how to reverse it so that the greyscale version is showing first and then the colored version would fade in. It seems to me that would have been the more logical way to do this, I have played around with it but I must be missing something because I can't get it working. Any ideas?

[johanafm]

You achieve this in the exact same way wether you show colored or grayscale version first. In fact, you don't even need to use two versions of the same image. You might just as well have one image of a ball and one of a guitar...
The only thing you'd change is which image is set as background for the anchor element and which is used as src for the image element.