The FTC also criticised Snapchat's 'Find Friends' feature, which was breached in a huge security attack and allowed hackers to gain access to 4.6 million phone numbers and Snapchat usernames. However, the Federal Trade Commission (FTC) pointed out that Snapchat has not disclosed to its users that screenshots can be taken of the images sent through the app, and that there are a number of third-party apps that can be downloaded which save the images directly to the recipient's device. However, Snapchat's hook is that it self-deletes these messages after a short period of time, theoretically meaning that the images will not be stored on the receiver's phone. Snapchat provides users with a service that allows them to take photographs before sending the images to their friends, providing an image-based messaging service.