Well I feel like an idiot >.< that did the trick, I didn't know where to put the smoothing function, but I got it.
For future reference:
imgLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, scaleContentForPicture);
imgLoader.load(new URLRequest(itemElement.image.toString()));
function scaleContentForPicture() {
var smoother_bm=Bitmap(imgLoader.content);
smoother_bm.smoothing=true;
}