Photo Gallery without fading effect

I´ve been trying to remove the fading effect from the photo gallery tutorial on this site. (This is the one if you do not know which tutorial I´m refering to: http://www.kirupa.com/developer/mx/photogallery.asp. But I haven´t been very successful in my attempts i´m afraid :-\

What I´d like to do is to instead of having the fading effect beetwen each image, I´d like to hide the loading picture beneath an MC containing a mask and have it to make the following thing:

When the forward button is pressed, the MC containing the mask is closed and thereby hiding the picture MC, the next external jpg is then beeing loaded in to the picture MC, and when it has finished loading, the mask MC is told to open itself and thereby “unfolding” the loaded jpg.

I hope that this makes sense and that someone of you nice people can give me a push in the right direction on how to accomplish this.