Another Cautionary Tale about iCloud Photos - Photostream

Member @Sylvan in a recent MPU Forum thread described failure of iCould Photo Library to sync properly, requiring Herculean recovery efforts and an “above and beyond the call of duty” backup strategy to recover lost photos. Link to that instructive MPU forum thread:

The following is another tale of woe with the use of iCould Photos, in this instance the Photostream function.

TLDR summary : Photostream, when used in a particular way to transfer photo files among IOS and macOS devices in multiple steps, can corrupt the photo files. The affected photos exhibit loss of color and dynamic range, associated with smaller image file sizes compared to the original image files. (See images below.) I suggest that you spot-check samples of your Photostream-transported image files and compare them to the original image files from your camera’s memory card. Direct attention to the file sizes, color and dynamic range. You might consider avoiding Photostream and instead use another method for transferring photos into your Mac’s Photos app library.

Details of my experience:
During a 2-week cruise to Scandinavia and the Baltic region I took several thousand photos with an Olympus M4/3 camera, with images saved to high-quality SDHC memory cards in the camera. Each evening the day’s image files were backed up to a 9.7” iPad Pro using Apple’s Lightning to USB3 Camera Adapter. No problems were observed during the trip with images displayed in the camera’s view screen or on the iPad. No images were edited or deleted during the trip. Image files were retained on the two SDHC cards.

After returning to the U.S. I made an overnight stop at a family member’s home. Both my iPhone (6Max at that time) and the iPad Pro were connected to a wi-fi network overnight. Details are not clear, but I think that all of the images in the iPad were transferred to the iPhone by Photostream over wi-fi since both devices had Photostream enabled (but not iCloud Photo Library). It is possible that at least some of the images were transferred by Photostream during the trip as well, since there was a spotty wi-fi connection on board the cruise ship.

After returning home, both the iPhone and iPad automatically connected to my home wi-fi network. After my home iMac powered up, the images appeared in the iMac’s Photos library, apparently imported by Photostream. Like the two IOS devices, the iMac did NOT have iCloud Photo Library enabled.

As a first step in a backup procedure, I transferred the image files from the 2 camera SDHC memory cards to the iMac by mounting the SDHC cards into the iMac and saving the files using the Finder in dedicated locations in the iMac’s Downloads folder. These images (directly from the SDHC card) were NOT imported into the iMac’s Photos app. Apparently the images already in the iMac Photos app had already been imported through Photostream from either the iPad Pro or the iPhone.

All images were created, saved, transferred and backed up as above during a three-week period.

In subsequent days I noticed that a number of the images, as viewed in the iMac’s Photos app, were “muddy” in appearance. Colors were muted and dynamic range was reduced. The file size of each affected images was smaller than that of “normal” images, typically 6 MB file size vs 8.5 MB file size for the images obtained directly from the memory cards. In addition, there was no data displayed for the “corrupted” images in the image histograms in the Edit function of the iMac Photos app.

Two versions of a photo are shown below; the first version demonstrates lack of dynamic range, muted colors and lack of information in the image histograms in the Photos app edit function. The second version is the uncorrupted image - better colors and dynamic range, image histograms are normally displayed.

I initially suspected that there was a corrupted memory card. Subsequent tests tended to rule that out. The images transferred directly from the memory cards to the iMac were normal. The only corrupted images were in the iMac’s Photos app. These images had apparently been transferred through Photostream from the iPad to the iPhone, then from either the iPhone or iPad to the iMac. Not all of the these Photostream-transferred images were corrupted; I estimate that about 10% were corrupted.

I no longer use Photostream to transfer images. I now import images into the Photos app through USB cable connection from the iPhone (for iPhone-created images) or by mounting a my camera’s memory card into the iMac.

Has anyone else experienced this problem? Can anyone explain the technical details of the Photostream process? Are there situations (low-bandwidth wi-fi, for example) in which Photostream compresses image files? Is the image file corruption described above typical for Photostream-transferred images?

What about Air Drop? Does Air Drop reliably transfer image files?

If Apple is going to rely so heavily on cloud storage for the Photostream and iCloud Photo Library functions, it seems that an integrity check of the image files should be a part of this functionality.


To be fair, I turned off iCloud Photo Library. Because … reasons.
See @Sylvan’s post. Link above, more than you ever wanted to know.

I was hoping that Photostream would work to simply transfer images and avoid the iCloud Photo Library drama.

Alas, no.

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This and the other thread are scary stuff.
I think I’m going to export all my photos tomorrow.
Thanks for sharing your experience, and possibly saving some of us the trouble.


In a word, no. Unfortunately.

Thank you so much for your detailed report of another huge photos related iCloud problem.

Pictures in iCloud Shared Albums are saved as lower resolution photos but afaik Photo Stream was advertised as an alternative to transferring pictures via a cable. So in theory, this should definitely not happen. Reading this, I’m glad that I’ve solely used it to transfer pictures between my iOS devices. I never turned it on on my Mac and just transferred pictures via a cable.

I tried to do a bit of research and came up with this short paragraph in a kbase article:

What resolution are My Photo Stream photos?

On a Mac or PC, your photos are downloaded and stored in full resolution. On iPhone, iPad, iPod touch, and Apple TV, your photos are delivered in a device-optimized resolution that speeds downloads and saves storage space.

Dimensions vary, but an optimized version of a photo taken by a standard point-and-shoot camera will have a 2048 x 1536 pixel resolution when pushed to your devices. Panoramic photos can be up to 5400 pixels wide.


I really hope that Apple improves their Photos syncing. Losing documents is unacceptable but losing Photos is almost like losing memories.

Sorry, but this is a hilarious and appropriate typo on your part LOL

I recently ran into the issue where I moved my Photos library to an external drive. After reconnecting, the Photos app spent a couple of days re-syncing to iCloud, never finishing more than 3% of the photos. I disconnected/reconnected to iCloud and it then went into ‘updating’ status for a long time. It seems to be good now, but this made me reconsider my entire photo workflow. Then I read these articles… :open_mouth:

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That is a really good typo indeed. :smile:

These times where one has to wait for ages only to then realize it got stuck somewhere during the process are really problematic. Crossing my fingers that everything is fine.

Photostream has worked like this since ios 5 and OS X Lion. It hasn’t quite been deprecated but they haven’t been pushing it since icloud photos came out.

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Yes, hilarious, and thanks for pointing this out. I wish I could take credit for this being deliberate, but it was a typo … my typing frequently goes into dyslexic mode :grinning:

Maybe instead of referring to iCould Photos I should have re-named it “iWishiCould Photos”


Were you shooting RAW or JPEG with the Olympus?

I use iCloud Photos for my iOS photos. For my DSLR photos, Canon in this case, my workflow is to copy the photos from the SD card to my Mac’s external drive “Originals” folder with dated subfolders for each camera over the years, GoPro, drones etc. I then triage these non iOS photos in Lightroom, “develop” the best and move those to the Photos app on my computer where they get synced to my iOS devices. Sometimes I shoot 7 way brackets and there’s no need to have all 7 versions in the Photos app.

A camera that shoots RAW and JPEG “develops” the JPEG itself from the RAW photo in a way to make it look its best - bright colors, saturation etc. When you import the RAW to Lightroom, Lightroom may by default apply a more conservative processing which looks muddy compared to the JPEG. You see the bright, colorful JPEG first and then when you touch it, it goes muddy because Lightroom loads the RAW to work on. In Lightroom you can select the profile to apply to the RAW photo, for example Adobe Standard, Adobe Vivid etc. This is only a starting point for your own processing using the histogram. I use Lightroom because that’s how I learned to do what I do; I also previously used Aperture. Although Photos is gaining the same functionality, I still can’t edit the same way I do in Lightroom.

Your “corrupted” photos look to me like RAW photos that have been “developed” by a different choice than the one that created your “good” version of the photo. I’m wondering if this is just because the Photos app created the JPEG from the RAW in a different way than than your camera.

Now here’s my issue with the DSLR / iPad / away on a trip situation.

When I’m on a trip with iPad and no Mac, I may take DSLR RAW photos and load them in to Photos via a card reader, just to see what I got. I find that iCloud Photos tramples all over the filenames, so I want to delete the photos from iCloud when I get home and use my Lightroom workflow. However, sometimes the photos remain on the iPad and then next time I connect iPad to Mac, the photos all get loaded up to iCloud again. I have the lowest cost Adobe plan with Lightroom and Photoshop but very little cloud storage, so I don’t use Adobe Creative Cloud for storing anything right now. I also don’t want to be uploading GB of photos over celluar on trips. Looks like I need to rethink this side of things.

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JPEG. Mostly by mistake. Just before the trip I updated the camera’s firmware. This reset the camera’s settings to default or factory-new mode, so my previously-chosen image-save mode of JPEG + RAW was reset to JPEG only. Like my typing skills, my paying-attention skills are, well … suboptimal.

Since that trip I re-enabled the "save to JPEG + RAW mode, but I don’t know yet how to process the RAW images.

Probably not, since I’m pretty sure that images from this trip were JPEG only. But this is an excellent thought. It makes me wonder - what does the macOS (or the iPadOS) Photos app do with RAW images? And what workflow should I use to handle this? I like your straightforward workflow, keeping image processing under your control.

Thank you for the excellent “JPEG/RAW Image Processing for Dummies” tutorial. Just what was needed to help me rethink my procedures. I should probably bite the bullet and get started with Lightroom.

What I learned about photography was back in the film-SLR days and darkroom-printing days. I have only recently become serious about digital image processing. It’s great fun, but frustrating when unintended consequences (like Photostream) get in the way.

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Lightroom is now on an Adobe subscription plan. $10 a month for Lightroom Classic + Photoshop + 20GB of cloud storage, or Lightroom only + 1TB of storage. $20 a month for Lightroom + Photoshop + 1TB.
I’ve had Photoshop for a long time so I go with the low cost Lightroom + Photoshop + 20GB.
I learned a lot of Lightroom from which got taken over by LinkedIn which got taken over by Microsoft. I also learned quite a bit from YouTube.
The iOS + Mac Lightroom wasn’t feature complete last time I tried to use it, so I haven’t made much progress with it.
I just discovered that Lightroom can assemble timelapses using its slideshow feature, so I’m trying that out.

I like your $10/month choice with limited cloud storage, combined with your own local storage + local backup + user-chosen cloud backup plan (Backblaze, for example).

And I like avoiding iCloud Photos and Photostream drama.

Interesting. Regarding slideshows created by Lightroom, how can one display these? I assume that you could display the slideshow on your own computer from within the Lightroom app, correct? And that would display the photos in “full” resolution, correct?. How would you display your Lightroom-created slideshow elsewhere? Export to a “movie” file (MP4, AVI, MOV)? Wouldn’t that degrade the resolution of the photos? Or is there a way to display the slideshow so that the photos are displayed in full resolution (or at least in the maximum resolution allowed by the display screen)?

Please correct me if I am misunderstanding this. I love slideshows, with various transition options, fade-ins, fade-outs, Ken Burns effects, etc. But I don’t really need a “movie” per se - in other words, a 30fps or 60fps motion picture that creates a huge movie file but still (possibly) degrades the original image quality.

Note that courses are available through some local libraries.
Sadly, our local library discontinued Lynda, but substituted a similar service “Universal Class” that happens to have a couple of Adobe Lightroom courses.


Be prepared for it to take a L-O-N-G time. I have about 700GB of pics/videos/data, and it is transferring from iCloud to Dropbox at a frozen snails pace. :snail:

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Lightroom uses its slideshow functionality for timelapses. The goal of a timelapse is to create a video, so I’m more focused on the target resolution of the video than preserving the resolution of the individual photos.

The presets used to set up the slideshow for timelapse can be found on the adobe site here: or if you want to read the whole article start here:

I also found a way to hack the frame rate. Suppose you want to use 1/3rd of the photos in a folder to make the resulting movie 1/3rd of the length. You can set up an icon view in the Finder with 3 icons per row. Then just select the first column of icons and copy them into another folder. Lightroom is ok with using your choice of folder as the source for a timelapse. GoPro Quik imports the photos to its own folder structure and try as I might I have not been able to get it to recognise a folder that it did not itself import.

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That is one gorgeous photo!