Unloading an image, loading new one in same MC

hey peeps, I have a movie clip that I load images into. Some of the images are png’s and are transparent in spots. when I load them the old image still shows underneath it. it never went away.

i thought when you load a new image in the same MC it replaced the old one, not covered it only.

So is it easy to keep the old image in place until ready to load the new one?

Do I clear the loader class or the MC? How?