Curtis Harkrider , Sep 06, 2009; 09:40 p.m.
Sensor damage is possible but unlikely since most sensors have overload protection. The roundish gray spots could be lens flare from the sun outside the field of view. You could take some shots against a blank white wall to see if the artifacts are still there. Another possibility is there is dust on the sensor or on the back of the lens. If you clean the back of the lens and the sensor window and you still see spots you might want to send your camera in for evaluation.