Another privacy intrusion river crossed by facebook,
the uploading of your facial portrait as captcha being tested.
That is why I never had any facebook account and on a second thought now my wife has neither.
(But tracking of non-facebook users still goes on through links on webpages).
Read: https://www.wired.com/story/facebooks-new-captcha-test-upload-a-clear-photo-of-your-face/
Another round in facilitating a better global surveillance, and you can help them do it, if not think twice.
polonus