I’ve seen this pop-up before on my android phone. I think it’s something to do with your app (i’m not sure from your screenshot whether that’s a browser or a client app like Sync) not having permission to access your media files. You might be able to give that app media/file permissions in your phone’s settings and that will stop happening.
My only issue with this is that it’s been posted in the Lemmy Shitpost community, and it’s not shit at all.