how do i use gifs?

public class Loading_screen extends World
{
    GifImage Loading = new GifImage("LoadingScreen.gif");
    /**
     * Constructor for objects of class Loading_screen.
     * 
     */
    public Loading_screen()
    {    
        // Create a new world with 600x400 cells with a cell size of 1x1 pixels.
        super(500, 500, 1); 
        prepare();
    }
    
    public void act()
    {
        Loading.getCurrentImage();
    }
    
    /**
     * Prepare the world for the start of the program.
     * That is: create the initial objects and add them to the world.
     */
    private void prepare()
    {
        
    }
}