Get the width

i know this has been asked before but i just can’t find it.

let’s say i have an empty movieClip. it’s width is obviously 0. then i use loadMovie() to load a jpg into the clip. now i want to find the width of the movieClip(ie the jpg) but the _width property still traces 0.

so how can i find the width of a jpg that i dynamically load?

thanks,
BS