A candid picture of a celebrity can fetch a large sum of money for paparazzi; anywhere from $1,000 to $10,000 in some cases. A photo that catches them in an embarassing or scandalous situation can earn much more. If a photographer were to snap a celebrity in the nude it's guaranteed money in the bank.
It's not easy to pity the rich and famous (especially if they're walking around naked) but, if it were you, and your naked or embarassing photo could get a single paparazzo upwards of $100,00... don't you think you would become a bit paranoid whenever you took a shower?
I suggest that the only way to counter act this would be to flood the market and devalue your nudity by never putting clothes on at all. Red carpets, trips to the store, dinner at the Ivy- all totally naked. After a week the pictures would be worth nothing, tabloids would get sick of reporting it and move on, and you would be free to work on your tan wherever the hell you felt like it. I'm talking to you Jessica Alba.