Guide

How Grain Photo handles your files

Last updated November 10, 2026

This page is a plain account of how Grain Photo treats your files: what it reads, what it writes, what it stores, and when anything travels beyond your Mac. Our privacy policy covers accounts, the website, and diagnostics in formal terms.

Your originals

Grain Photo reads your photos and videos in place. Browsing, searching, rating, tagging, and collecting never move, rename, edit, or delete an original. The folders you see in Finder stay exactly as they were.

Two actions change what you see without changing files on disk. Turning a folder off in File > Source Settings… removes it from your library in Grain Photo. Choosing Hide From Grain for one or more files, after confirming, removes them from the gallery. In both cases the files remain where they are.

Export Original… writes a copy of the original to the destination you choose. It refuses to overwrite the original itself.

Ratings, tags, and other edits

Ratings, color labels, Tags, descriptive fields such as title and caption, custom fields, and collections are stored in Grain Photo’s own catalog on your Mac. They are not written into your files or their XMP sidecars.

Ratings and keywords that another app saved into a file or sidecar are read and shown. Imported keywords appear read-only under More details in the Inspector, and you can search and filter by them. If you change a rating in Grain Photo that Lightroom also set, Grain Photo shows its own value and keeps it even if the file is read again later. Lightroom won’t see the change, because nothing is written back.

This is the trade-off: editing in Grain Photo is safe for your files, and it stays in Grain Photo. For anything that needs to travel with the file, make the change in the app that owns the file.

Previews and search data

To make a library browsable and searchable, Grain Photo keeps an index, previews, and the results of on-device analysis on your Mac. Analysis runs on your computer; searching by description does not upload your media.

Previews are derived images, not copies of your originals. Their storage limit is set under Preview storage in General settings, between 8 and 32 GB. A preview cache is not a backup, and it can’t stand in for a missing drive.

Previews are what let you browse a disconnected drive. Opening the original, exporting it, or opening it in another app still needs the drive. Sources and navigation covers offline sources.

When something leaves your Mac

Ordinary browsing, search, and organizing stay on your Mac. Some things you do involve another service or app, and it’s worth knowing which.

Your account. Signing in, activating the app, and checking for updates contact Grain Photo’s servers. These requests carry account and licensing information, not your library.
Dropbox. If you connect Dropbox, Grain Photo reads from your own Dropbox account to list folders, build previews, play videos, and fetch originals when you export or copy them. Previews are cached on your Mac, and the files stay in Dropbox.
Handing a file to another app. Open With, Copy File, dragging, and Export Original… give the file to the app or destination you chose. What happens next is up to that app.
Local tools. Scripts and assistants on your Mac can work with your library only after you turn on Allow local tools under Connectors in settings. An assistant you authorize may send information to its own service. Check that app’s permissions and data handling before sharing media with it.
Diagnostics. Share diagnostics in General settings is optional. When it’s on, Grain Photo may send crash reports, app actions, and performance timings. It never includes images, file names, paths, or search text, and it’s separate from your account.

Local analysis and search do not require uploading your library. Account requests, Dropbox access, optional diagnostics, and the apps you authorize have the separate roles described above.

Access and recovery

Grain Photo asks before it reads a folder, and it keeps that permission for the folders you’ve added. If permission to a connected source is lost, a Restore source access… button appears in the title bar. Confirm the same folder to continue. Nothing in your library is removed while access is missing.

For questions about your account or the information we hold, see the privacy policy or write to info@grain.photo.