2012 Year in Review: Most viral photos

As networks began calling the race for President Obama on election night, his campaign tweeted this photo with the caption “four more years.” The image became the most retweeted ever and “most liked” on Facebook. (@BarackObama/Twitter)

As networks began calling the race for President Obama on election night, his campaign tweeted this photo with the caption “four more years.” The image became the most retweeted ever and “most liked” on Facebook. (@BarackObama/Twitter)