I am trying to create a shared album in iCloud, containing about 750 photos and 50 short videos.

Using Photos both on iOS 9 and El Capitan, the process of adding the photos to the album is extremely slow.

On iOS, when I try to share the photos I am shown a modal "preparing" dialogue that doesn't seem to progress.

On my Mac (which does not have "Optimize Storage" enabled) the sharing progress bar fills slowly, then stays mostly filled for a very very long time, while heavily using the CPU.

Given the amount of network traffic that is caused by the request, I assume that Photos is trying to download/re-upload each image.

Given that the photos are already stored on iCloud, I would expect to be able to share the photos instantly, as I can do with Google Photos.

Is this the expected behaviour or am I suffering from an abnormal issue?

EDIT: added photo of iOS dialog

preparing modal dialog

Adding one photo to a new shared album works ok, but as I add more photos in one go the time taken scales up quickly.

  • It was really really slow for me too. I had to leave it on for almost a day to back up my photo library of about 8000 photos.
    – owlswipe
    Commented Jun 6, 2016 at 20:47
  • But let's do some troubleshooting nonetheless! It took that long for me because of the slow internet connection at work. Please go to www.speedtest.net and perform a wifi speedtest. Comment back (start your comment with @JohnRamos) with the download and upload speeds you recieve.
    – owlswipe
    Commented Jun 6, 2016 at 20:48
  • @JohnRamos I'd understand why it's slow to perform the initial library backup - uploading lots of files can take a while. But my point is that there shouldn't be any uploading or downloading taking place - my photos have all already been uploaded to iCloud. My problem is not uploading to iCloud photo library, but adding 800 photos from that library to a shared album.
    – stonesam92
    Commented Jun 6, 2016 at 20:51
  • @JohnRamos If you're saying that adding photos to a shared album does require reuploading the photos then I guess that answers my question about whether this is intended behaviour, but if that's the case then that's very disappointing, and another reason to use Google Photos over Apple Photos. It also makes managing large shared albums from iOS incredibly painful since, unlike the initial upload which runs in the background, a sharing photos displays a modal dialog which prevents you otherwise using the app
    – stonesam92
    Commented Jun 6, 2016 at 21:01
  • Ah, I understand. Please show me a picture of this "modal Preparing dialogue" (you can edit your question with it). What happens if you do this (do it even if you've done something like this already, please!): go into Photos on your Mac, go to the shared tab, create a new shared album, share it with one person, then press Add Photos and Videos and just add one basic photo to it. How long does that take?
    – owlswipe
    Commented Jun 6, 2016 at 21:03

2 Answers 2


What happens during the Preparing step is Photos first downloads all the photos/videos being shared (so this step can be skipped on a device that holds full-resolution copies of your photos). You also see this step when trying to share a photo by email or iMessage, with Optimize Storage enabled.

Then it will downsample photos to 2048 pixels on the long edge (5400 pixels for panoramas), and videos to 720p. This step takes place locally, consumes a lot of CPU power, and may take a very long time, particularly with videos. That would explain why you can share a single photo fairly quickly, but then the progress indicator seems stuck once you select everything. I’m almost positive it’s your videos incurring this extra processing time.

Finally, Photos will re-upload everything to a separate iCloud server, which is exempt from your storage quota. However, each shared album is limited to 5000 photos/videos combined, with videos themselves limited to 5 minutes long.

Do note that these steps appear to occur asynchronously. However you’ll still ultimately be bottlenecked by either your CPU or Internet upload speed.

I would advise you to do this from your Mac, if possible. Not only can you leave it plugged in overnight, prevent it from sleeping, and continue using it while it’s doing its thing, the resampling step should be much faster with your Mac’s CPU than with your iPhone’s (generally speaking).

  • 5
    ARE YOU KIDDING ME?!? I'm absolutly stunned that Apple has applied so little intelligence to this feature...
    – RJR
    Commented Apr 17, 2017 at 8:35
  • 1
    It is very disappointing; however photos appear to be an area of importance to Apple. I would suggest you voice your concerns. Hopefully improvements can find their way into future versions of iOS/macOS/iCloud.
    – user11633
    Commented Apr 17, 2017 at 12:50
  • 1
    I don't buy the resizing taking ten to forty seconds locally. GraphicConverter can do a similar resizing in a second.
    – WGroleau
    Commented Sep 16, 2018 at 2:42
  • 2023, was conned into trying an iPhone again, and here I am stunned at the same stupidity. In what world does it make sense to download everything, that already exists in the cloud, back to my phone, just so it can back to the cloud, solely so I can share the things that are already in the cloud. I don't know if it's possible to design this any more horribly =(
    – Justin
    Commented Aug 4, 2023 at 23:45

As you can read here https://discussions.apple.com/thread/7609292?start=0&tstart=0 the pictures are downloaded firstly to your computer to be later compressed and re uploaded to a different server, which only allows 2048 pixel width images.

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