I can't stand this practice either, but hotels have always waived the charge when I explain that I didn't drink the water. If they were truly determined to fight me on it, I doubt it'd help if I had pics of full water bottles.

The only complete assurance would be if you took the bottles to the desk upon check-out. But even that would only guarantee success for a one-night stay, as the charge could have been applied to an earlier night (before housekeeping supposedly "replaced" the bottles you drank).

Since I have never failed to get the charge waived simply by asking, I'm not going to bother taking pics or lugging water to the desk. If I ever encounter a situation where asking doesn't work, I'd simply dispute the charge. Good luck to the hotel trying to prove that I drank their water.