All Planets (no matter if it’s the first Planet immediately after registration or a newly colonized one) start with a default Planet picture which is randomly chosen from all free Planet pictures.
Player can change the picture of any of their planets, for free, at any time, choosing from all unlocked planet pictures in the "Edit planet" menu located on the "Planet" page.
Initially there are 5 unlocked pictures that any player can use. Apart from them there is a wide range of locked pictures which can be unlocked by paying a certain amount of Credits (5). Unlocking a picture costs Credits, changing pictures doesn’t. Once unlocked the picture remains at the player’s disposal for the account’s life time in the respective game universe, regardless of Round restarts and account restarts.
pictures are separated into 8 categories, according to price. The first category contains free pictures, they are always open to all players. The other categories contain pictures that cost, 10, 50, 100, 150, 250, 500 or 1500 Credits each.
On a Team planet, each Alliance member can unlock a picture by purchasing it with Credits, but only the Alliance leader can actually change the picture of the Team planet.
If you want to purchase new Planet picture you can follow the link (1) in the "Edit planet" (2) popup or open the Premium menu (3) and find "Planet picture" (4) menu.