Most mobile operating systems provide a built-in functionality to automatically backup your photos/videos in a secure cloud(internet) based storage account. By turning that service on you minimize the risk of losing irreplaceable photos/videos should something catastrophic happen to your phone. You'll be able to access the cloud based backup and restore them.
And for mobile operating systems that don't offer this option built-in, there are options via apps you can install. Eg. Dropbox, Google photos, Microsoft onedrive, etc.