One solution is to limit the number of photo's to a given count or say the last x days.
Personally I never use the slide show option, so that's not an issue for me. I prefer to pick 'n choose which pictures I want to see and for how long.
I've been thinking about hacking this "virtual category" idea myself, but if the powers-that-be here think it's worthwhile, I can let them take a crack at it .... hmmm or contract that to me
