After purchase of my Nook Color, I noticed many images were already loaded on the system. Although some look appealing, I really didn’t wish keep all of them, so I decided to delete them from the Nook.
To remove factory installed images from your Nook, click the real ∩ button on the surface of the Nook Color, and tap the screen menu button at bottom centre. After the menu appears, tap the extras button. On the extras screen, select Gallery located at top right, which then opens a grid of images. Select the image you wish to remove, open the menu once more and tap the delete button on the right side of the menu. After tapping OK on the Delete dialog, the image will be permanently removed from the Nook Color.
Tap the top left screen shot above for a step-by-step view of the process.