Googling this question gives a wide variety of results but I don’t see anyone actually asking or answering it so…wtf?
Long press, nothing but share, delete, archive, or add to album. No sync, download or anything of the sort. Is immich supposing it’s a one-way trip? What if I want a photo I backed up a year ago, I have to open the webui?
Share button can export any photo. For photos only in the cloud there is a download button to sync to your device at the top when you open the picture.