After recharging the battery, everything seems to be back to normal. However that has me puzzled- was it the battery or the camera? I hope it's the former... I'm going to try and drain the battery and see what happens.
A bad battery can cause odd behavior. But, the camera should recognize a low voltage condition and turn itself off (versus producing strange photos).
It could also be a defect that onlyreveals itself when the camera is hot. I'd make sure to give it a good workout.