yes, you can, but it is very dangerous. You can open your tama, take out the battery and take off the back cover. Then you have to unscrew the circuit board, raise that up, and take out the small card that sits there. This is the background card (or what you see behind your tama on the screen) from there you can change it with another from a different tama, make your own, or even decorate it your own way. Just be very careful not to damage anything in there....
KM