[Feature] Advanced duplicate resolution options to prevent mobile re-upload loops

[Maxima356]

I have searched the existing feature requests, both open and closed, to make sure this is not a duplicate request.

• Yes

The feature

Describe the feature you'd like

When a user imports an external library (e.g., old phone backups or a family archive) and then connects a mobile device via the Immich app, it often generates a massive amount of duplicates.

Currently, Immich's duplicate mechanism operates on a quality-first basis. I would like to request more granular logic/options for handling these duplicates automatically during or after the import process.

Specifically, adding the following logic options in the duplicate/import settings:

1. Keep highest quality (Default/Current behavior).
2. Prioritize Mobile Upload / Prefer Mobile Asset: Automatically resolve duplicates by keeping the version uploaded by the mobile app and removing/hiding the duplicate originating from the external/imported library.

Describe the injury or frustration this causes

Without this option, users have to manually review and delete thousands of duplicates.

Even worse, if a user manually deletes the wrong version of a duplicate (the one the phone thought it successfully backed up), the mobile app might detect it as "not backed up" and trigger a complete re-upload of those photos, creating an endless loop of duplicates. Sorting 1,500+ photos by hand for multiple family members is a painful user experience.

Describe alternatives you've considered

• Using the current "Duplicates" page, but it requires manual approval for every single pair/group of assets, which doesn't scale well for large initial library imports.
• Deleting photos directly from the phone, but that defeats the purpose of having a seamless, automated mobile backup strategy.

Additional context

This feature would make onboarding family members (who often have overlapping photo histories or existing manual backups on shared drives) much smoother and prevent the mobile client from fighting against the server's deduplication state.

Platform

• Server
• Web
• Mobile

[bo0tzz]

The deduplicate mechanism on upload doesn't (and won't) do anything smart like this, it's purely based on matching whether an already uploaded file (so not from an external library) has an identical contents checksum.
I'd suggest you wait for the workflows feature to mature, and then use those to get the specific behaviour you want.