ActionScript 2.0 :: Photo Gallery - Last Image Clicked By User Not Disappear

I have just started using flash. I needed to do this presentation for a client. In one scene I have provided him with a photo-gallery, where some 30 photos are placed randomly ...when playing the movie (published as projector) user will click any photo to watch it. For this I have used swapdepth so that photo, user clicks comes to front. Also applied drag to all these photos.

My code look something like this:
on (press, dragOver) {
startDrag(_root.pic6);
} on (release, rollOut, dragOut) {
stopDrag();
} on (press, release, dragOver, dragOut) {
_root.x +=2;
_root.pic6.swapDepths(_root.x);
}

For doing this first I converted the photo to button ...then converted this button to a movie clip and gave a instance name to this. Then I went into the movie clip and applied the above code to the button placed inside the movie. Applying all this to all photos I placed them randomly on timeline. The problem is : code is working fine, it is dragging photos, bringing them to front etc. But I have user to go back and play another scene to continue the presentation. Problem starts here, the last photo clicked by user remains there, even though it is not present in that scene.