Nextcloud app, andro/ios : is it normal?

hi guys

I installed on my ios 12 the nextcloud app from appstore
it looks like (as an android) that after logged in on a server, and enabled the backup of my pic albums, that the pictures are not only backed up on the server (this is what I want) but also copied to another nextcloud album (means just a copy on the device on all pics), what I do not want.
why do I have 1GB taken by nextcloud app (inluding photos) instead of only do a copy on the server?

I have gigabytes of pics to backup, hope it doesnt copy each on a second album within the device… could you confirm (or correct) my thoughts please?

I thank you vm

When the app uploads any file, it stays in the app’s cache. You can clear the app’s cache under Settings > Advanced.