Massive Facebook outage reveals how the company automatically tags your photos

Facebook's suite of apps, including Facebook, Instagram and WhatsApp, suffered a massive outage on Wednesday, with many users complaining they were unable to view or upload photos on the apps.

The company finally resolved the issue at around Thursday morning - over 8 hours after users started reporting problems.

During the outage, many users noticed that, in place of their photos, Facebook was displaying the image tags that had been automatically assigned to those images.

Facebook is known to use artificial intelligence (AI) to identify objects and people in pictures and assign tags.

The primary purpose of this is to describe photos and videos to users with visual impairments, as part of the company's accessibility efforts.

What's not clear, however, is whether Facebook also uses this information to target advertisements.

There is a great deal of data about users' lives contained in these images - such as what their hobbies are, whether they have got a pet, whether they have got a beard or wear glasses, and so on.

This may include information that users have chosen to withhold from Facebook in other ways.

Judging from the reactions on Twitter, many users were unaware that the social network was analysing their photos in this way.

While Thursday’s outage may have been a major inconvenience for some, it did help to shine a light on how much of the visual world has become machine readable.