Performance and Cache

Seula caches thumbnails and stack-detection data. macOS can reclaim this storage when disk space is low.

What is written to disk

Seula writes only metadata into photo folders: into JPEG files or .xmp sidecars next to photos. See Metadata and compatibility. Other data stays outside photo folders:

• Thumbnails and stack-detection data are stored in a system cache.
• Settings, such as theme, language, and shortcuts, are stored on your Mac.

Seula does not create a photo library or send data over the network.

Thumbnail cache

The cache makes large folders open faster. Stack-detection data uses a few kilobytes per photo. Seula keeps the cache below 2 GB and removes the oldest data first. If macOS clears the cache, Seula rebuilds it when needed.

Manage it in Settings ▸ General ▸ Advanced:

• Cache thumbnails on disk: turn this off to keep thumbnails only in memory.
• Clear thumbnail cache now: remove the disk cache. Settings also show the space used by thumbnails and stack detection.

Loading photos

• A RAW photo appears first at working resolution, then sharpens to full quality. Zooming can load more detail. See Working with RAW photos.
• Seula prepares neighboring photos in the background.
• Rapid metadata changes are written together.

Ratings are saved automatically. You do not need to clear the cache before quitting Seula.