Queen Elizabeth II has posted her first Instagram image.

The media-savvy queen posted from the Science Museum Thursday to help promote the museum's summer exhibition.

Using an iPad, she shared an image on the official royal family Instagram account 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. "

The royal Instagram account was launched in 2013 and has 4.6 million followers.