Animation: *.gifs flood memory

Good morning

I wrote an applet with 18 sets of animated images. One set consists
of 22 images (.gif, each image is 2K in size). The user can repeatedly load as
many sets as he desires by the click of a button. The thing now is that
apparently each time a new set is loaded it is uncompressed (from .gif)
and stored in the users memory. Very soon the users memory is full and
warnings about memory lack pop up. Or even worse the applet stops working.

I am using a media tracker. Each time the user loads a new set by the click of a button, the old set gets 'disconnected' from the variable myImages[i], but still remains in the memory. I actually only need one set of images present.

Question: What can I do?
Can I remove the "swimming" (in the memory) image files form the memory by
java code?

I very much appreciate your time, "Mug"

Some code:

/* loadImg */
    public void loadImg( int iG, int iV, int iP, int
                         iR) {
        stop();
        ...
        //set img name
        imgFileName = ...
        for (int i=0; i < numOfImages; i++) {
            String fullImgName = imgDirName +"/"+ imgFileName + i +".gif";
            myImages[i] = getImage(getDocumentBase(), fullImgName);
            myTracker.addImage(myImages[i],i);
        }
        //media tracker
        try { myTracker.waitForAll(); this.showStatus("Loading images
        done"); start();}
        catch (InterruptedException e) {
            System.out.println("An exception occurred: " +
            e.getMessage());
            e.printStackTrace();
        }
    }


    /* update */
    public void update(Graphics g) {
        paint(g);
    }

    /* paint */
     public void paint(Graphics g) {
        g.drawImage(myImages[currentImgNumber],20,20,this);
     }