Just don’t … in most states it’s illegal and you probably don’t want to test that theory to find out; it’s so not worth it.
It’s a CONFIDENTIAL government document and only approved/qualified officials (which is not you) are authorized to duplicate it; in some states, its A FELONY. This includes on web sites, Facebook, Instagram, Live Journal, My Space, any social media or whatever. If you are caught, you could be fined, and/or arrested and possibly miss your chance to vote and yes, if you are incarcerated, you could potentially lose your right to vote! No they cannot void your vote, but you don’t want to journey down that road either. If you’ve already posted your ballot to the web, DELETE IT IMMEDIATELY and hope that Google Search hasn’t already indexed it. If it has, then you can contact Google to request to have the picture purged. You can request an urgent removal from Google results here:
The laws on documenting voting are determined by your state so the penalty for taking pics of your ballot is not the same in every state. You can check here to see what the penalty is for taking pics of your ballot in your state.