Why is my Galaxy S8+ keep deleting my photos and gifs?

[Android Central Question]

So I recently updated my Galaxy S8+ to Oreo, and after the update, my gifs that I downloaded from google or somewhere else started to disappear. I thought I erased them by accident so I downloaded them again, and made a separate album to put them in. A day passed, I didnt touch the album, but the gifs disappeared. Is this happening to anyone?