I just bought a Blue/Black 3DS XL with Mario Kart 7 preinstalled on the SD Card. On the card there is folder structure like this:
- DCIM
|
+- 100NIN03 (it's the folder where the pics get stored)
- Nintendo 3DS
|
+- 9a24bc4467d2e389849f758287798754
|
+-...
