Originals are saved at `{downloadDirectory}/YYYY/YYYY-MM/YYYY-MM-DD/YYYY-MM-DD.{fileID}{ext}`. The date is the photo's `takenAt` in local time, and `downloadDirectory` defaults to `./photos`, resolved when the library opens. The old `originals/` layout is gone.
`photo.download()` writes the original to `savePath`. It copies from the cache when the cache holds the original, and fetches otherwise. `lib.backup()` uses the same path and rule, and every album in `collections/` links to it. `isLocal` is true only when the original is at `savePath`.
For a file in several albums, one rule picks the copy everything uses: the most recently synced, with the lowest album ID breaking a tie.
Model: opus-5-5
Bounds the originals cache and evicts least-recently-used. cacheOriginalsMaxBytes default 100 GiB; the effective limit adapts down via fs.statfs to keep freeBelowBytes (default 50 GiB) free. Over-limit writes evict unpinned originals oldest-mtime-first (mtime touched on read); pinned files (favorites + latest week) are skipped and an over-budget on-demand fetch proceeds over-limit. Every in-flight write is excluded from eviction, so concurrent fetches never delete each other's just-stored file. Only cacheDirectory/originals is evicted; downloadDirectory and thumbnails never.
Model: opus-4-8