MADISON, Wis. (AP) -- Here's a caution for Wisconsin voters: If you're the type of person who likes posting photographs to Facebook or Twitter, do not post pictures of your completed ballot after you vote in next month's recall election.

The state Government Accountability Board points out that doing so constitutes election fraud under Wisconsin law. It would be a Class I felony, punishable by up to 18 months in prison and a $10,000 fine.

It's illegal to show your marked ballot to anyone. GAB spokesman Reid Magney says the law was intended to prevent people from selling their votes and then showing their ballots as proof they voted as requested.

Magney says he's not aware that anyone was ever convicted under the law, but that the GAB wants people to know the rules.