This is something I haven't looked into much. I just have my stuff stored on my own cloud server but I would like to make sure it is encrypted as well. Is there a way to do this for video files and photos?
iCloud does this by default. I know that. There are tons of options for Windows and Linux as well. There are also browser based clouds that will do this. I believe Nordlocker is one of the most popular ones that specifically offers encryption for pictures and videos. You can look into that to get an idea.
Nextcloud provides several methods for encrypting photos, primarily through server-side encryption and end-to-end encryption. So you can host your own server and have your own cloud that also has encryption built in. It is a really good option and free too!