Zelda: Wind Waker Easter Eggs

When you enter the room in Hyrule where you recieve the Master Sword, look around the outside walls of the room. You'll see stained glass portraits of the Seven Sages from Ocarina of Time, as well as one of Ganon.

To enter the nintendo gallery all you need to do is beat the game once and get the COLOR pictograph box and show it to the guy in the gallery once you have unlocked the door.