Size of image loaded in mc

hi! anyone know how to determine the dimensions of a jpeg after loaded in a movieclip? I’m trying to set xy positions of other clips off the root relative to the image. So, in the main timeline I’ve got:

_root.attachMovie(“ImageObject”, “myimage”+count, count+1);
obj = _root[“myimage”+count];

Right now, my ImageObject is just an exported movie with nothing on it. Image loads just fine, my problem is, what’s the height and width of the image (cuz any pic of any size could get loaded)?

Thanks to any and all…