You can assign an image on your gallery as wallpaper on Samsung Galaxy Note 2.

• From the Home screen, tap Apps > Gallery icon.
• Select a folder location and tap a file to open it.
• With the image displayed, press Menu key and then tap Set as.
• Select one of the two options:
  • Home screen assigns the current image to the home screen background. This image is spread across all available screens.
  • Lock screen assigns the selected image to the background for the lock screen.
  • Home and lock screens assigns the current image to both the Home screen and Lock screens.
• Touch and drag the crop box anywhere on the picture. Touch and drag the sides of the crop box to zoom in or out to create a cropped area.
• Tap Done to assign the wallpaper image.

or

• Tap Cancel to stop without updating the wallpaper image.