External Images

I have an empty movieclip that is loading external jpg’s into it using loadMovie. The image sizes vary (ex. 30X40, 70X50). If the movieclip is defined to a certain size (ex. 100X100), is there any way to have the images center horizontally and vertically automatically? I know how to do this with actionscript and the widths/height values of each picture, but I was wondering if there’s an easier way.

Thanks.