Media Thresher finds duplicates, blurry and broken shots, straightens tilted photos, repairs damaged videos, fills in missing locations and fixes the date in the Finder – right on your Mac. Your photos never leave it.
Starting point
Photos and videos live on your Mac, on a NAS, in cloud folders and in the Photos library – often twice, sometimes broken, rarely with a location. Media Thresher brings order to them without you having to look at every photo yourself.
Case study
Media Thresher grew out of a real private collection: around 158,000 photos and videos in folders on a NAS, plus a Photos library with around 93,000 more, stored in iCloud.
The result: around 315 GB can be removed, 17 GB of it already cleaned up – storage that no longer needs backing up or syncing. For every photo and video, the best file is kept.
| Task by hand | Assumption | Hours |
|---|---|---|
| Look through 250,410 files once to find duplicates and bad shots | 2 seconds per file | 139 |
| Decide 33,518 groups of duplicates and similar photos | 15 seconds per group | 140 |
| Straighten 18,309 tilted photos | 30 seconds per photo | 153 |
| Check 9,459 videos for errors | 10 seconds per video | 26 |
| Convert 821 old videos to MP4 | 1 minute per video | 14 |
| Compare 1,426 groups of duplicate videos | 1 minute per group | 24 |
| Crop 242 screenshots | 30 seconds per photo | 2 |
| Find and assign places for 109,069 photos in 671 folders | 3 minutes per folder | 34 |
| Set the file date in 1,422 folders with an extra tool | 2 minutes per folder | 47 |
| Save 1,205 Live Photos as photos in Photos and delete the Live Photo | 30 seconds per Live Photo | 10 |
| Total | about 590 |
Not included: matching the camera’s time to the iPhone to the minute so camera photos get the iPhone’s location and the right date. That is hardly feasible by hand.
Features
From duplicates and old videos to missing locations and wrong dates: each tool takes care of one typical problem in collections that have grown over the years. The (i) next to each heading explains in the app what the section does.
Finds exact duplicates that are completely identical, and also similar photos – the same photo in a different size or quality. The best photo is already preselected to keep.
Tracks down photos you probably don’t want to keep. You set the thresholds with sliders, and the list updates instantly.
Straightens tilted photos, turns photos lying on their side and crops away unneeded borders – browser bars in screenshots, white margins around documents or memes, black bars. You see a preview before anything changes.
Rescues damaged videos and makes old formats playable again – as a modern MP4 file that every Mac, every iPhone and the Photos library understand.
Finds photos and videos that no longer open properly – such as interrupted copies or incompletely saved files – and tells you what to do with each one.
Fills in missing locations. Existing GPS data is never overwritten.
When files are copied, macOS gives each one a new date. The Finder then shows when a photo was copied, not when it was taken. Media Thresher sets “Created” and “Modified” back to the capture time.
A Live Photo is a photo plus a three-second video – and the video usually takes more space than the photo. Media Thresher turns them into regular photos. Just like on the iPhone, you can pick a different frame from the video.
Moves photos and videos from folders into the Photos library, or exports them from the library into folders. It always transfers and verifies first, then cleans up.
Sources
Media Thresher works with the Photos library, folders on your Mac, cloud folders and network storage.
Including photos stored only in iCloud – they are downloaded in portions.
Photos and videos in folders on your Mac.
iCloud Drive, OneDrive, Dropbox, Google Drive and Box.
NAS, for example from Synology or QNAP. Anything you sort out goes to the NAS recycle bin.
Privacy & safety
All analysis runs locally, using the image recognition built into macOS. And anything you sort out can be restored.
Photos and videos never leave your Mac – the analysis runs entirely on the device.
Only for Places, the app asks Apple’s map search: with folder names like “Peru 2018/Cusco” and with coordinates to work out place names and time zones. Photos and videos stay on your Mac.
Files go to the trash of their location – the Mac’s Trash, the NAS recycle bin or “Recently Deleted” in Photos. Files are only deleted for good if you explicitly confirm it, for example on a NAS share without a recycle bin.
Straightening and cropping show a preview first, and whole runs can be undone, as can assigned places and file dates. When moving, converting and with Live Photos, files are transferred and verified before anything is cleaned up.
How it works
Folders, NAS, cloud folders or the Photos library.
Media Thresher examines your photos and videos right on your Mac.
Look at the matches up close, adjust thresholds, accept or change the preselection.
Whatever you sort out goes to the trash of its location – and can be restored.
FAQ
No. All analysis runs locally, using the image recognition built into macOS.
The only exception is Places: it asks Apple’s map search with folder names like “Peru 2018/Cusco” and with coordinates to work out place names and time zones. Photos and videos themselves are never transferred.
There is no fixed limit. Media Thresher is built for large collections and is tested on a collection of around 250,000 photos and videos (more than 2.5 TB) on a NAS and in the Photos library.
The first analysis of a very large collection does take time, on a NAS several hours. You can pause it at any time, and it picks up where it left off. After that, the app only reads what is new or has changed.
A Mac with Apple silicon (M1 or later) and macOS 14 Sonoma or later. Media Thresher does not run on Intel-based Macs. The app is available in English and German.
Media Thresher works with folders on your Mac, network storage such as Synology or QNAP, iCloud Drive, OneDrive, Dropbox, Google Drive and Box, and the Photos library – including photos stored only in iCloud, which are downloaded in portions.
Media Thresher never deletes anything permanently without your explicit OK. Files go to the trash of their location – on your Mac, on your NAS or in “Recently Deleted” in Photos – and can be restored from there.
Since this is a beta, we still recommend a current backup.
No. Since 31 March 2025, Google only lets other apps access photos and videos that the app uploaded itself. No other app can read your Google Photos library anymore, and Google’s interface never allowed deleting. So Media Thresher can neither find duplicates there nor clean anything up.
Supported are Apple’s Photos library, folders on your Mac and on your NAS, and cloud folders such as iCloud Drive, OneDrive, Dropbox, Google Drive and Box.
Nothing. The beta is free. In return, we ask for your feedback – what works, what doesn’t and what’s unclear – in a short video call of 15 to 30 minutes.
The beta is available on request. Send us a short note saying which Mac you use and where your photos are stored. We’ll then email you the download link. After a few days with the app, we’ll talk about your experience in a short video call (15–30 minutes). Participation is subject to our beta terms.
For every photo without a location, the app looks for the best source, in this order:
A copy with a place. If the same shot exists once more, for example in the Photos library, and it has a place, the photo takes it over.
The iPhone at the same time. A camera photo gets the place of an iPhone photo taken shortly before or after. To do this, the app matches the camera’s clock against the iPhone.
The folder name. “Peru 2018/Cusco” becomes Cusco in Peru, via Apple’s map search.
A photo from the same day. Whatever has no other source gets the place of a photo in the same folder taken in the hours before or after.
Before writing anything, the app shows a sample. Places are only written when you start it: to the Photos library through Photos, to files with ExifTool. It can be undone.
No. Photos that already have GPS data never get a different location – whatever the source.
Often, yes. Media Thresher checks the videos in your folders and rescues whatever is still readable from damaged files into a new MP4 file. The original stays in place until the repair is complete.
Old formats such as AVI, WMV or MKV are converted to MP4, keeping the recording date. Copy-protected videos are recognised, and the app tells you that nothing can be rescued there.
During the analysis, the app takes a quick look at every video. The full check plays every video once from start to finish and so also finds errors in the middle; you can pause it at any time.
When files are copied, macOS gives each one a new date. If you ever copied your photos to a NAS or a new drive, the Finder often shows the date of that copy. The actual capture time is still stored in the photo itself (in its EXIF data).
The File dates tool sets “Created” and “Modified” back to the capture time. For phones, that is the real time from the file. If a camera’s clock was wrong, the app corrects the time using the iPhone photos from the same day. The content of the files stays unchanged, and the old date can be restored.
Only what you select becomes a regular photo. The new photo carries all capture data and takes over favorite, albums, keywords, title and caption. Only once it has been checked does the Live Photo go to “Recently Deleted”, where you can get it back for 30 days.
Just like on the iPhone, you can pick a different frame from the video as the photo. Live Photos with an effect, such as Loop or Long Exposure, stay as they are.
Both tools write to real files and are new. Try them on a few folders first and check the result. Both can be undone: assigned places as well as the old file date.
Yes. A click on a thumbnail opens the photo large. There you browse with the arrow keys, select or deselect with the space bar, and for straightening and cropping you see the result in advance. Next to each heading, the (i) explains what the section does and what happens to your files.
Beta
Media Thresher is in beta. You get the app for free, we get your feedback – so Media Thresher gets even better with real collections.
The beta is available on request: tell us briefly which Mac you use. We’ll email you the download link. In return, we ask for your feedback in a short video call (15–30 minutes). Our beta terms apply.
Was something flagged as a duplicate, blurry or a screenshot when it isn’t? Was something missed, or a location assigned wrongly?
How fast is the analysis with your NAS, with cloud folders or with a large Photos library?
Are texts, hints and buttons clear – in English and in German?
Where did something go wrong, and what did you do just before?
Screenshots often help us with the analysis, and we treat your data confidentially. A short description, your macOS version and the type of source (for example NAS or iCloud) help us too. How we handle your message is described in our privacy policy.
Apple, Mac, macOS, iCloud, iPhone and Live Photos are trademarks of Apple Inc. Synology, QNAP, OneDrive, Dropbox, Google Drive, Google Photos and Box are trademarks of their respective owners. Media Thresher is not affiliated with these companies.
