I also did it with this.

While you can change it afterwards, it might be worthwhile to check a setting in immich on how it organizes the photos on disk you upload.

I changed it to year/month/photo-id because I find it convenient, but it does not organized them like that for backups.

You can change it at a later date and run a job to “fix it”, but it might be worthwhile to set it up correctly from the start ( if this matters to you ). So no harm done if you change your mind later.