MovieClipLoader question

Im having problems with assessing the size of an image after having loaded it into a movieclip using MovieClipLoader.

Im trying to use the onLoadComplete-method to determine when the image is completely downloaded into the imageholder-mc, but Im just getting the original size of the mc, not the image’s.

Am I using the MovieClipLoader incorrectly somehow?

var MCL = new MovieClipLoader();  
MCL.loadClip("IMAGE.jpg", mc_ImageHolder);
MCL.onLoadComplete = function (targetMC) {  // perhaps 'targetMC' should be used?
   trace (mc_ImageHolder._width);  // outputs mc's original size, not image's size