A 13GB database of at least 100,000 Snapchat images that users thought had been deleted has been released by hackers who have been collecting the files for years.

The Snapchat files were posted online via the website viralpop.com, a fake website that installed malware on computers trying to download the images. The site has since been taken offline, but not before thousands of people already accessed the Snapchat collection.

The collection of photos reportedly include a large amount of child pornography. Half of Snapchat's users are between 13 and 17 years old.

In a statement, Snapchat confirmed the images in question came from third-party sites, but denied hackers had breached the site's servers:

We can confirm that Snapchat’s servers were never breached and were not the source of these leaks. Snapchatters were victimized by their use of third-party apps to send and receive Snaps, a practice that we expressly prohibit in our Terms of Use precisely because they compromise our users’ security. We vigilantly monitor the App Store and Google Play for illegal third-party apps and have succeeded in getting many of these removed.

This is not the first time Snapchat has had issues with users' data. In 2013, Snapchat users' phone numbers were accessed through its app and some 4.6 million usernames and phone numbers were leaked. And this year, hackers used Snapchat to send photos of fruit smoothies to thousands of people.