Mask over script

Hi All,

is it possible to have a mask over this script:
_root.createEmptyMovieClip(“emptyMC”, 1);
_root.emptyMC._x = 25;
_root.emptyMC._y = 25;
i = Math.ceil(Math.random()*6);
_root.emptyMC.loadMovie (“random/” + “0” + i + “.jpg”)
stop();

??

what it does is load a picture and centers it, what would be nice is to have a mask over it… something like this:

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muchas gracias for your help,
m.