It's hilarious. Back in 2009 Fox announced, and sent a memo, stating they would have zro tolerance for on-screen errors like that.
"Effective immediately, there is zero tolerance for on-screen errors. Mistakes by any member of the show team that end up on air may result in immediate disciplinary action against those who played significant roles in the “mistake chain,” and those who supervise them. That may include warning letters to personnel files, suspensions, and other possible actions up to and including termination, and this will all obviously play a role in performance reviews."
Now we have this "mistake". I guarantee you, it wasn't an accident. May have been a mistake, but it wasn't an accident. Tina Fey's impression is great, but anyone can tell the difference. You don't accidentally run a picture of an ex-SNL member instead of the ex-Governor of Alaska.
This seems to be the work of someone who doesn't like Palin, someone at Fox who isn't Fox-conservative (OMG!). It's one thing not to like Sarah, it's another to run a photo of Tina Fey. Whoever ran that image of Fey turned that Fox News Report into Weekend Update. It was hilarious. And they'll probably get fired for it.
David Clark, Fox News' executive producer of weekend programming, issued an immediate statement:
"This past Sunday during America's News Headquarters, a graphics error was made during a segment on former Alaska Governor Sarah Palin. The producer has since been disciplined and an explanation and apology will be made in the same hour next Sunday. Fox News regrets the error."