Dropbox backup can automatically upload image and video files. (Album structure, tags, comments, notes in the app are not backed up, so please use iTunes for a complete backup.)
After logging in to Dropbox, open the album information screen of the album for which you want to enable backup, and turn on automatic backup.
After that, the upload will be executed automatically when the application returns to the home screen, so there is nothing special to do. On the Settings > Dropbox backup screen, a list of albums for which automatic backup is turned on will be displayed, so you can check the backup status here.
If there is an error, the error will be displayed in red on the above screen and the backup will be suspended.