Already thinking about that perfect voting booth selfie on Election Day? You may want to think again.

Taking a cellphone shot of yourself that includes your marked-up ballot could be considered a felony.

According to reports, a provision of the Illinois election law forbids showing others your ballot. It dates back to decades before the smartphone era, but would apply to digital photographs.

Ken Menzel is deputy general counsel of the Illinois State Board of Elections. He explains that the prohibition is meant to thwart vote-buying schemes by making it harder to prove to someone after the fact that you did vote a certain way.

Technically, that makes it illegal to post ballot images on social media, though Menzel says he's never heard of a prosecution.