[Feature] Add granular "Deny Original Download" permission for local instance users in Shared Albums

[luddinho]

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

• Yes

The feature

Is your feature request related to a problem? Please describe.

Currently, when sharing an album with an existing local Immich account, the lowest assignable permission tier is Viewer (read-only). This role implicitly allows the user to download original, high-resolution source files.

Describe the solution you'd like

I propose introducing a new checkbox or permission tier for local user sharing: "Deny Original Download" (similar to the toggle currently available for Public Share Links).

• How it should work: When enabled for a specific local user or group on a shared album, the native Immich mobile app and web UI should hide the "Download" button. The server should only serve compressed/downscaled web-optimized previews (.webp / JPEGs) to their client timeline and interface, blocking direct API pipeline access to the original source file.
• Benefits to the user: This allows instance owners to share photo collections with internal users (like family members or acquaintances) without forcing them to switch to a browser window via a public link, while still successfully protecting original high-res assets from being extracted.
• Goal: Bridge the feature disparity between Public Share Link permissions and Local Registered User permissions.

Platform

• Server
• Web
• Mobile