While Facebook allows you to post as many pictures as you like, and tag yourself in pictures that your friends have taken, the Web site only allows you one profile picture, so make it count. You may very well have some potential suitors on the Web site, so be sure to portray yourself as accurately as possible. A clear, well-lit picture of you will help you to put your best foot forward, particularly if it's a portrait or captures you in the midst of one of your favorite activities. And you might ought to refrain from using one of the pictures from that New Year's Eve party, as your profile picture is accessible to everybody on Facebook, even with the privacy settings engaged.