She consistently shrouds her face under covers and wigs.
The photo has a watermark from a photograph office and a message saying there were an extra 14 photographs of the vocalist.
Her say of Christmas could be a think reference to her happy collection called Everyday is Christmas.
Someone is apparently trying to sell naked photos of me to my fans. Save your money, here it is for free. Everyday is Christmas! pic.twitter.com/aeQlnTwLuy
— sia (@Sia) November 7, 2017