So take the picture, dispose of the ballot and get a new one from the election officials. Fill the new one with your own choice, get it stamped and put it into the ballot box. A bit of a hassle to be sure, but it does not exactly derail democracy.
whatever increasingly convoluted suggestion you'll make next probably doesn't work either.
I also don't appreciate your arrogance in trying to shut down this discussion pre-emptively. Maybe try listening more in the future, you might discover interesting things even if they don't agree with your pre-set ideas.