Go to the art gallery in the special features section. Go to the picture before the one you wish to use as the background. Press right to switch to the image you desire, but in the time after the first image has disappeared and before the desired image appears, when the screen is black, press B. You will return to the special features menu with the desired image as the background
Go to the Passcodes screen in the Options Menu. For the codes with more than one part, enter the first part of the code and you will hear a beeping implying that you entered it incorrectly. Immediately enter the next portion of the code and you should get the correct R2-D2 beeping telling you it has been entered.
Hold the L and R triggers while selecting your mission to skip the hangar and fly in the default craft.