What does iOS photo optimization really do?

First I need to explain why I have between 70,000 and 75,000 photos. I’ve been using iPhones since the iPhone 3. For years I couldn’t depend on automatic backups, so I periodically had to back up manually. Now I have multiple copies of hundreds, possibly thousands of photos and I haven’t had the time to delete the duplicates.

I have optimize photo storage on both my iPhone and my iPad. My iPad shows I have only 12 GB of photos and only 45 GB out of 256 used. But I wasn’t able to back up to my MacBook pro with 139 GB free space. After hours working with Apple Mac support it backed up, but shows a backup of 147 GBs. An iOS support rep claimed this is because an iTunes backup includes everything on the iPad. She couldn’t explain what Optimizing iPad Photo Storage was doing if it wasn’t optimizing iPad photo storage. This is also the same situation with my iPhone.

Is this just my problem? Does anyone else see this?

By this, do you mean downloading as many photos as possible (with margin for error on storage space) to the iPad?

This is one of the two reasons I run a Mac Mini to hold the true Photos library and back it up to BackBlaze.

There should be a few apps for iOS to help you delete duplicate photos off your iPhone or IPad.

Optimizing Photo Storage on any device is designed to do the same thing. It is going to store a smaller compressed version of the image on your device while uploading the larger, full res image to your iCloud storage.

It sounds like before you try to troubleshoot this any further you really need to get the duplicate images deleted. It is hard to say how many duplicate copies may be found…and there may be more on one device than on another.

After that is cleaned up, there are system tools that can tell you what types of files your storage is being allocated to. But it is premature to start troubleshooting there when you are already aware of all of this wasted space due to the dups.


Maybe you can help share some insight. I’m hesitant to optimize my photos. I’m afraid that if I do want to print a photo I won’t have access the finest photo. My older iPad mini tells me to optimize when I open Photos. However, I have other newer iOS devices which have plenty of space. They are all backed up, in the Cloud.

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As was said, the original high-quality image goes in the cloud. The originals of any images or videos that you select (for viewing, manipulation or printing) get retrieved from iCloud before they’re available for upload or manipulation.Good overview here:


So Katie, your iPad Mini is recommending this to you because it apparently has less storage available than your newer devices do.

If your device has plenty of available storage, you won’t see that message. In that case you have the option to keep the full, high res images on your device.

Personally I keep that feature turned on regardless of the storage space I have available. By doing so, I don’t have to worry about turning it on or off depending on how much I am shooting.

Since I can still print the full res image either way the only advantages to keeping them on my device is saving a couple seconds (or less) to download the full res image and of course some additional internet bandwidth.

Unless you either have an extremely slow internet connection or your ISP charges you for the amount of data you download each month, there is no reason not to keep the feature turned on.

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Thank you so much, rhuvela!

@geoffaire alluded to this, but there is a reason to turn it off for non-iOS devices: backups. If you maintain a Mac with the feature turned off (IOW, all photos are downloaded to that device’s Photos library in their original resolution/quality), you can back up to another service like BackBlaze. If you turn on Optimize Photos, your original images exist only in iCloud. Photos deleted from iCloud storage are subject to their 40-day recovery period vs. whatever (likely longer) recovery period you have with other services.

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With a true backup service like BackBlaze and even Time Machine, deleting a photo from your current library should not delete it from your previous backups at all…at least that is how it has been explained to me, (In the case of Time Machine, the backups containing the images may eventually be overwritten if you do not change to a different hard drive when your drive is full.)

However, you are correct that all of the sync services such as iCloud, Google Drive, Dropbox, etc will delete the image from the synced copy of your data on their server once you delete it from your library.

I think Dropbox may offer versioning now, although I’ve heard it is kinda pricey! But if you have versioning available, that is another way to preserve your original so the next sync does not delete it.

In addition to any other backup locations, all of my original images are downloaded and stored on an external RAID 1 drive that has no other data on it.

It depends upon your retention period. If you never expire a backup, then you are correct, the photo will never go away. However, if you drop old files from the backup after a set amount of time (for example, I have Arq configured to delete unreferenced objects after 180 days), they will disappear from your backup.

Last I checked, 30 days was included in the free tier of service. And it saved my bacon once.

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