[Feature] Persistent, preloading offline cache for thumbnails and previews as known from Google Fotos and iCloud Photos

[1661410107114145152525]

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

• Yes

The feature

Summary

Add a feature to Immich’s mobile app that allows users to pre-cache thumbnails and medium-resolution previews up to a user-defined storage limit (e.g., 20–30 GB).
This cache should be persistent and controllable by the user, enabling smooth offline browsing of recent photos and videos — similar to how Google Photos and Apple Photos manage local content.

Motivation

Currently, Immich only caches thumbnails and previews when they are viewed, and this cache can be automatically cleared by the mobile OS or the app.
This causes problems when users want to browse or show media in environments with poor or no internet connectivity.

Example:
At a festival, I wanted to show vacation photos from last year. Many images and videos failed to load, because they were not cached in advance. Same issue when I was in a train and also in a forest. I don't want to download everything as I want to use Immich as my single source of truth with albums and more.

Proposal

• Allow users to set a cache size limit (e.g., 30 GB) for offline thumbnails and previews.
• Provide options to cache:
  • The most recent photos/videos
  • Specific albums or favorites
  • Photos only, or photos plus videos
• Cache should be downloaded proactively in the background without manual scrolling.
• Cache must be persistent and protected from automatic OS cleanup.

Benefits

• Immich can be a real replacement for Google Fotos even in bad connection situations
• Smooth offline access to media in all situations, even with slow or no internet.
• User control over what is cached offline and how much device storage it uses.

---

This feature would greatly improve the usability of Immich on mobile devices, especially in low-connectivity scenarios. I would love to hear your thoughts or if this is on any roadmap. Maybe persistent cache steering might be a great addition to your workflows plan too as it might affect a large user base (even the older members of my family use such features regularly on their iPhone with Apple Photos, as it occurs seamlessly in the background, significantly reducing friction)).)

Platform

• Server
• Web
• Mobile

[bo0tzz]

#4466