Old photos never die

Jake Widman
Friday, 22 May 2009 01:11

Business IT - Security

A study from the University of Cambridge has found that photos shared on social sites are often still accessible even after the user has deleted them.

In a post on the University of Cambridge Computer Lab's Light Blue Touchpaper blog, PhD student Joseph Bonneau describes an experiment he and his colleagues conducted on 16 photo-sharing sites.

The post, entitled "Attack of the Zombie Photos," points out that more than 40 billion photos are on Facebook alone and that the site gets more than 25 million new photos each day.

Bonneau explains that dealing with such volume means that most photo-sharing sites don't host all their photos on the main site server.

Rather, the photos are stored on a separate dedicated photo server, which delivers the requested photo on receipt of the proper URL.

The problem comes with the fact that if a user deletes a photo through their profile, it isn't actually removed from the photo server. Rather, similar to the way deletions via the Recycle Bin or Trash Can on a personal computer are handled, the photo can sit there until it is overwritten.

During that time, if someone knows the direct URL for the photo, they can still retrieve it.

For what the experiment discovered, see Page 2.