Synctrain (iOS) – “Backup New Photos” reprocesses existing photos daily

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1

Hello, I always start the backup manually inside the app, because background synchronization is not possible on iOS.

I think this may be related to iOS and not to Syncthing. I would like to know if other users see the same behavior.

I use Synctrain on iOS for photo backup into a Syncthing folder.

When I manually start “Backup New Photos”, the app processes many photos again, even though no new photos were taken or changed since the last run.

Example: One day it processed 148 items. On other days it processed several hundred (sometimes up to about 700). The app shows no “Recent Changes”.

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Conditions:

  • There are no new photos in the library
  • Optimize iPhone Storage is disabled
  • No files were changed or moved manually

Still, each manual backup processes many already existing photos again.

Expected behavior: Only truly new photos should be processed

Questions:

  • Is this behavior known?
  • Is there a technical reason why unchanged photos are processed again?
  • iOS re-indexes photos in the background from time to time. Could this cause the photos to appear as changed?
  • Is there a recommended configuration or workaround?

Thank you for any hints or advice!

PS: I translated it via DeepL

2

Hm, it may be just saying it saved photos while it actually skipped them. Does it take the app as long to ‘save’ photos every time, or is it quicker than when it saves new photos?

3

Hi, thanks for your feedback.

I just triggered “Backup New Photos” (Neue Fotos sichern) again. After 2 days (I had not taken any new pictures), it reported that around 900 photos were saved, but the whole process completed very quickly, and nothing appeared under “Recent Changes” (Kürzliche Änderungen).

So it might indeed be the case that the app only reports that photos were processed, while they were actually skipped.

For testing, I then took two new pictures. After that, it showed “2 items saved” (2 Elemente gespeichert), and under “Recent Changes” (Kürzliche Änderungen) I can see exactly those two images. That matches the expected behavior.

Overall, that is a bit confusing.

4

Right, so the count is a bit exaggerated but apart from that, the back-up seems to be working as intended. I wil look into the counter.

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5

Nice, I have Syncthing installed on a Pi4 with EndeavourOS ARM. Everything runs perfectly, and the backup photos are cleanly saved into the year/month folders as configured. I really like that!

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