I have created a Custom Backup plugin that allows a specified directory to be backed up when you do a backup.
I created this as I have a custom soundtrack directory containing playlists and album covers that I get backed up whenever I do a backup, to a zip file.

After install you will see a new menu item 'specise_8472/backup'.
Click on this and you will be presented with a dialog to enter a folder path to backup. (no trailing slash!)
Now when you do a backup this directory will be backed up to a zip file with the same name as the backup file.zip. and in the same place as the backup.
If you do not enter a path you will get a message that no custom path provided. If provided you will get a success message. This runs automatically after the main backup has finished.

The filepath is stored in a Backup.ini file that is created in the same directory as the plugin.

If you are doing a lot of 'partial' backups and this is annoying, then just open backup again and save with no path specified. This will put a blank entry in the ini file.
At any time you can change the path by entering a new path which will overwrite the existing path.

File can be found at    https://1drv.ms/f/s!AszUwF4_399MmjUaCSUi87shgGZ-
There is an installer .exe which registers it after install and the raw .dll for users who prefer more control.

To do,
Multiple directory's if a need for this.
Restore back on system restore

Cheers George

Thanks, but this is to allow backup of other dirs when doing an internal backup.
Not for backing up the main DB as it does a good job on its own.

Used by me for backing up a music dir that has HTML and pics in.