Leonardo da Vinci's Mona Lisa originally had eyebrows and eyelashes, a French inventor has claimed after digitally scanning the painting.
Pascal Cotte said his 240-megapixel scan revealed traces of facial hair obliterated by restoration efforts.
Da Vinci changed his mind about the position of two fingers on her left hand, her face was originally wider and her smile more expressive, he added.
Mr Cotte exhibited his findings at the Metreon complex in San Francisco.
He said he spent 3,000 hours analysing data from scans he made of the painting in the Louvre's laboratory three years ago. Mr Cotte, a French engineer, used infrared and ultraviolet sensors during the process.
His 22-gigabyte digital photo was made using 13 different colour filters rather than the three or four found in standard digital cameras.
The scan showed that the merchant's wife in the painting holds a blanket that has all but faded from view today, he said.
Mr Cotte also said his analysis revealed what he believed were the painting's original colours - light blues and whites, compared with its current heavy greens, yellows and browns.
"To communicate our cultural heritage to our kids, we need to provide the maximum of information," Mr Cotte said.
"With just one photo you go deeper into the construction of the painting and understand that Leonardo was a genius."
Mr Cotte has made high-resolution scans of more than 500 paintings, including works by Van Gogh, Brueghel, Courbet and other European masters.