This page goes deeper than the Auto Sync overview. It explains what gets uploaded, how to set up a sync rule, what to expect when Prismic is in the background, and what to try if something looks stuck.
What Gets Uploaded
Once you turn on Enable auto sync (in Camera roll syncing), Prismic uploads photos and videos from your camera roll that match your sync rules and haven't been uploaded before. Live Photos are uploaded along with their video. Items are sent oldest first.
- Nothing is uploaded until you have at least one sync rule. With no rules, a sync does nothing.
- Before the first upload, Prismic asks you to confirm with Enable Camera Roll Sync? so you can review the source, destination album and options first.
- Files larger than your server's upload size limit are skipped. If your server doesn't report a limit, files over 1 GB are skipped.
When Syncing Happens
- When you open Prismic — it checks for photos that haven't been uploaded yet.
- While the app is open — when new photos appear in your library, Prismic starts an upload a moment later.
- Sync Now — in Camera roll syncing, you can start a sync yourself and watch each upload's progress. Tap the cross on a row to cancel that item.
- In the background — at the times you schedule, covered below.
Only one sync runs at a time. If one is already in progress, a second request is skipped. Max concurrent uploads (1 to 5) controls how many files upload at once.
Setting Up a Sync Rule
Open Camera roll syncing and tap Sync Rules, then Add New Rule. Choose the server the rule belongs to, then open Rule Details:
- Sync from — All Photos (your whole library, the default), or one or more specific device albums.
- Add to — an optional album on that server. Leave it as none to upload without adding to an album.
- Auto sync items added after — turn on and pick a Date to ignore anything created before it. Useful if you don't want years of old photos uploaded.
- Delete originals after import? — permanently removes photos from your device once they've uploaded. This can't be undone, so Prismic asks you to confirm before enabling it.
You can have as many rules as you like, for example your whole camera roll going to one server and a single album going to another. If two rules would send the same photo to the same server and album, it's uploaded only once.
Sync rules are specific to this device and are not synced between your devices. An album-based rule never falls back to your whole library: if its album can't be found, for example because it was deleted or your photo access is limited, the rule is skipped and shows Album unavailable.
Foreground vs Background Sync
Turn on Scheduled Daily Backup under Background Sync to sync even when the app is closed, then add one or more Backup Time entries. Backup times are specific to this device.
Background work on iOS is controlled by the system, not by Prismic. To get the best results:
- Keep Background App Refresh turned on for Prismic in iOS Settings.
- Don't force-quit Prismic from the app switcher. iOS generally won't launch a force-quit app in the background.
- Expect delays in Low Power Mode, with a low battery or without a good connection. Prismic needs a network connection to run a background sync, but doesn't require the charger.
- Treat each backup time as the earliest start. iOS decides when the run actually happens, which can be later than the time you picked.
Before a background upload, Prismic refreshes its sign-in to each server, since the app may not have been opened for days. If iOS ends a background run early, uploads stop cleanly and pick up next time.
Large Backlogs Go Up in Small Batches
Each sync run uploads up to 5 items. If more are waiting, Prismic schedules another background run about an hour later, and keeps going until everything is uploaded. Opening the app or tapping Sync Now also uploads the next batch right away.
For a very large first sync, the quickest way is to leave Prismic open and tap Sync Now a few times, or simply let the background runs work through it over a day or two.
What You See While Uploading
In Camera roll syncing, Sync Now shows Syncing... while a run is active, with a row for each file showing its thumbnail and a progress bar. When it finishes you'll see how many photos were synced, or No new photos to sync.
After the uploads finish, Prismic waits about ten seconds to give your server time to process the files, then fetches the new items and runs a quick library update for that server. That's when they show up in your library with their real thumbnails. If a thumbnail is blank at first, it normally fills in after this update.
Already-Uploaded Photos Are Skipped
Prismic keeps a record on your device of every photo it has uploaded, and skips those on later syncs. Photos that fail to upload aren't recorded, so they're retried on the next sync.
Reset Sync History clears that record. Every photo is then evaluated for upload again, which may result in duplicate items on your server. Only use it if you really want to re-upload.
Limited Photo Access
If you gave Prismic access to only selected photos, Camera roll syncing shows Limited photo access. In that case:
- Auto sync only uploads the photos you selected.
- Device albums can't be chosen as a source, so only All Photos is available.
Tap Open Settings and allow access to all photos to sync specific albums or your whole library. If access is denied entirely, Prismic shows Photo Library Access Required and sync stays off.
Checking Your Server
In your server's library details you can see counts for your photos, videos and albums, the time of the Last sync, and a Sync Library button to refresh the library from the server. This is separate from uploading: it updates what Prismic shows, not what's sent from your phone.
Troubleshooting
Nothing is uploading. Check that Enable auto sync is on, that you have at least one sync rule, and that the rule's source album and server still exist. Camera roll sync can't be enabled until the app has finished its first library sync.
Background sync never seems to run. Make sure Background App Refresh is on, that Prismic hasn't been force-quit, and that you have a connection. Low Power Mode and a low battery delay it. Try scheduling a few backup times across the day.
Only some photos uploaded. Large backlogs upload 5 items per run. Wait for the next run, or tap Sync Now. Also check your rule's Auto sync items added after date and whether you have limited photo access.
A photo is missing a thumbnail. Your server may still be processing it. It should update shortly after the upload completes, or after a manual Sync Library.
I got duplicates. This can happen if you used Reset Sync History. Remove the extras in your PhotoPrism library.
My originals were deleted. That's the Delete originals after import? option on a rule. It only removes photos after they have uploaded successfully. Turn it off in Rule Details if you don't want it.
Still stuck? Use Report a Bug below and let us know what you're seeing.
Back to the Auto Sync overview.