Actually the baby bump photo is from 2006. Read this article and on page 2 you will see that the Anchorage Daily News (there’s a link to it) says the photo is from 2006. (It’s a gallery.)

http://www.associatedcontent.com/article/998402/vp_candidate_sarah_palin_pregnancy.html?cat=75

Also, if you go to forums/msg boards, you will see Alaskan residents saying they know its not true because Bristol doesn’t go to school in Anchorage, the photo is old/wrong, etc. etc.