The International Press Telecommunications Council has released a new study on the use of images by social media websites.
The study finds that some of the biggest social media sites ones, like Facebook, Twitter and Flickr, remove photographers' metadata from images photographers upload.
"A social networking site is only as good as the information its members choose to share," says Michael Steidl, IPTC's managing director. "If users provide rights data and descriptions within their images, these data shouldn't be removed without their knowledge."
The results show that Facebook and Flickr are the worst offenders, with most of the metadata removed from the original files uploaded. Twitter has also been found to remove Exif and IPTC metadata from its files.