The problem is that it's quite slow on my website (http://new.lordfpx.com), but I odn't think that comes from remooz, maybe it's a general javascript problemwhen it comes to resize a picture on a webpage, too bad, hopefully, browsers are now faster and faster.
I was using an old version of sleight+sleightbg, but I have a big problem with png background in DIV (the picture is scaled, so your script seems to be the solution, but, what are these pictures : "x.gif and "../images/blank.gif" ?