[Feature] Advanced photo selection algorithm with recency weighting and batch grouping

[Yo89]

I have searched the existing feature requests to make sure this is not a duplicate request.

• Yes

The feature

Problem Statement

Currently, Immich Kiosk offers basic sorting options (random, newest, oldest) for displaying photos. While these work well for simple use cases, they don't provide intelligent selection that balances recency with variety, which would create a more engaging slideshow experience that naturally emphasizes recent memories while occasionally surfacing older ones.

Proposed Solution

Add an advanced photo selection algorithm with the following capabilities:

1. Recency-based weighting

• Weighted random selection where photo probability is based on recency (e.g., photos from the last month have 10x higher probability than photos from 5 years ago)

• Configurable decay curve (linear, exponential, or custom thresholds)

• Configuration example:

  album_order: weighted_recent
  weighting:
    type: exponential  # or linear, stepped
    decay_factor: 0.8  # how quickly older photos lose weight
    time_unit: months  # days, weeks, months, years
  

2. Batch/Context grouping

• When a photo is selected, optionally display nearby photos from the same time period to preserve context and tell a story

• Configuration example:

  batch_mode:
    enabled: true
    window_size: 50  # consider 50 photos before/after the selected photo
    batch_size: 5    # randomly select 5 photos from this window
    display_order: chronological  # or reverse_chronological, random
  

Use case: When the algorithm selects a photo from a family vacation, it would automatically show 4-5 other photos from that same trip in chronological order, creating a mini-story before moving to another time period.

3. Album-level configuration

• Allow these settings to be applied globally or per-album

• Example:

  albums:
    - id: "FAMILY_ALBUM"
      album_order: weighted_recent
      weighting:
        decay_factor: 0.9
      batch_mode:
        enabled: true
        batch_size: 5
        
    - id: "LANDSCAPE_ALBUM"
      album_order: random  # traditional random for this album
  

Benefits

• Better user experience: Recent memories naturally appear more frequently without being repetitive
• Contextual storytelling: Batch mode keeps related photos together, recreating the flow of events/trips
• Flexibility: Users can choose between simple random, strict chronological, or intelligent weighted selection
• Reduced "dead" periods: No long stretches without seeing recent photos, even in large libraries

Alternative Approaches Considered

• Creating separate "recent photos" albums manually → requires constant maintenance
• Using newest sort → too predictable and repetitive
• Pure random → doesn't reflect that recent photos are typically more relevant

Additional Context

This feature would be particularly valuable for long-running digital photo frames displaying family/personal photos where there's a natural desire to see recent photos more often while still occasionally being surprised by older memories.