It's usual for many people to document your lives with photographs, but the voting booth may not be that place.
Several states have laws against bringing in photographic or recording devices into the polling place, and your smartphone counts as one of those devices, according to AllThingsD. California law states, "After his or her ballot is marked, a voter shall not show it to any person in such a way as to reveal its contents," and although it doesn't expressly say online, we think it's a good bet that it probably also means taking photographs of it with your smartphone.
Wisconsin recently informed voters not to tweet photos of their ballots or put them on Facebook -- but both state party chairs did so anyway (and then removed them.) And one voter in North Carolina was relieved of his smartphone when he whipped it out at the polling place.
We think it's great that people are excited to be voting and we applaud that. However, it's illegal in many states to take pictures of your completed ballot or bring in photographic equipment to the polling place. While we don't know if anyone will actually be arrested on election day for doing this, it will likely annoy polling place officials. Save your photos for outside of the voting booth and the building and save yourself a lot of trouble.