Use a file as the background image, with the planet to be superimposed upon it. This option is only meaningful with the -projection option. A color may also be supplied.
Erabili fitxategi bat atzeko planoko irudi gisa, bere gainean gainjarriko den planetarekin. Aukera hau esanguratsua da soilik - projection aukerarekin. Kolore bat ere eman daiteke.