The app indexes the photos in the folders you choose, and only those. The choice can be changed at any time from the Sync screen.
The app asks Android's MediaStore for every image and groups them by folder, largest first, with a photo count on each row. MediaStore is the only way to find photos without broad storage access, and it already leaves out files that are still being written and files in the trash.
Folders are shown the way Android names them, relative to the phone's storage: DCIM/Camera/, Pictures/Screenshots/, Pictures/WhatsApp/. A folder includes every folder below it, so ticking DCIM/ covers DCIM/Camera/ too.
On first run every folder under DCIM, where the camera saves by default, is ticked for you. Untick it or add others before tapping Continue.
- Open the Sync screen and tap Change folders.
- Tick and untick, then tap Save and sync.
- A sync starts: photos in newly ticked folders are added, and photos from unticked folders leave the index.
Each photo's id is the md5 of its absolute path on the phone, for example md5("/storage/emulated/0/DCIM/Camera/PXL_20260801_101500.jpg"). One function in the app computes it, for indexing and for every Re-Sync, so the ids on the phone and in the index are always built the same way.
- A photo moved or renamed gets a new id: the old document is deleted and the photo is added again.
- A folder that disappears (a memory card taken out, a permission withdrawn) simply has no photos at the next Re-Sync, and its photos leave the index. Put the card back and the next sync adds them again, from the phone's cache where possible.