Setting Loaded GIF as a Background

Question

Situation: I have a JFrame and I have managed to import the GIF and display it in the Main Panel however it moves all of my other panels down, causing my GUI to be

Answer 1

UPDATED ANSWER

Now in accordance with Oracle's Swing UI-guidlines as correctly indicated by @MadProgrammer

Best way to add a background is to simply paint it. Create a BackgroundPanel (extends JPanel) and override paintComponent(...);

public class BgPanel extends JPanel
{ 
    //Overload and paint your background
    public void paintComponent(Graphics g)
    {
        //create image object, or more preferably do that in the BgPanel constructor
        g.drawImage(image, 0, 0, null);
    }
}

In accordance with Oracle's guidelines for custom rendering when using Swing.