iPad app, does not sync photos after edition


I’m just starting with next cloud that I installed on my Synology NAS ( server 16.0.3) and on my iPad ( and could finally synchronise my 8000+ photos on my NAS. That’s pretty good !
I just wonder about the sync strategy between source (my ipad camera roll) files and dest files (I see in the app). After 1st sync, if I edit a photo in iOS photo app (eg I rotate it) in the camera roll, will it be sync’ed to the Nextcloud app ? At first I would say, it does not ; this is behaviour I observed from that simple test. In Nextcloud app, 1st time sync’ed photo remains, as well as on server data folder.

So my question here is, is it expected behaviour ? Shouldn’t the modified files from source being re-synch’ed to target ? Or is there a setting I overlooked that would help doing so ?

Thank you for your hints,