Hi @laura16! Can you talk us through what happened before the data/photos were lost? Is it possible that you might have backed it up to your Samsung account, Google account, Google Drive, Google+ or other cloud storage? Do you have a Google account synced to your phone? If you haven't backed it up anywhere it is unlikely that you will be able to retrieve the data. :smileysad:
Please don't worry, you can easily recover deleted pictures from your phone without backup before they are overwritten by using phone data recovery software. Usually, the deleted pictures can be scanned out and recovered to pc.