If I was Cera, I too would be unhappy at having my caption image disappear like that. 
I guess we best use our imagination. 
Cera: *singsong voice* "Oh Littlefoot!"
Littlefoot: "Huh? What is it, Cera?"
Cera: "The image is gone. They can't see us. We have the place all to ourselves now. You know what that means?"
Littlefoot: "Ah, yes. I think I do." *mischievous grin*