But be aware, there was a bug detected when you try to migrate JoomGallery 3 (local) to JoomGallery 4 (cloud):

Error when migrating to an external file system · Issue #204 · JoomGalleryfriends/JoomGallery
If you set up an 'external file system' and carry out the migration, the images are not displayed. Reason: The 'filesystem' column in the database table…
github.com