Queen Elizabeth II has posted her first Instagram image. The media-savvy queen posted on the official royal family Instagram account from the Science Museum to help promote the museum's summer exhibition. Using an iPad, she shared an image of a letter from 19th century inventor and mathematician Charles Babbage to Queen Victoria and Prince Albert. The queen's post said: "In the letter, Babbage told Queen Victoria and Prince Albert about his invention, the Analytical Engine, upon which the first computer programs were created by Ada Lovelace, a daughter of Lord Byron." Following her post, the royal family account shared a video of the official crowning moment. The royal Instagram account was launched in 2013 and has 4.6 million followers.