Optimize iPhone Storage:
what it does and when it helps.

What Optimize iPhone Storage does

With iCloud Photos on, every photo and video you take is uploaded in its original format at full resolution. With Optimize iPhone Storage on as well, iCloud keeps those originals and your iPhone keeps space-saving versions. It is on by default when you turn on iCloud Photos.

iOS makes the room when the iPhone needs it, starting with the photos and videos you open least. So the Photos figure in iPhone Storage may not drop while there is still free space.

How to turn on Optimize iPhone Storage

1. Open Settings, tap your name, then tap iCloud.
2. Tap Photos and make sure Sync this iPhone is on.
3. On iOS 27 or later, tap iPhone Storage. On iOS 26 or earlier, the options are already on this screen.
4. Choose Optimize iPhone Storage.

What stays on your iPhone

A space-saving version of every photo and video stays, so your library looks complete. The originals are in iCloud and can be downloaded over Wi-Fi or cellular, which means you need a connection to get one back at full size.

When Optimize iPhone Storage does not help

It only covers Photos: apps, messages and downloads take the same space as before. It needs room in iCloud, because when iCloud storage is full, new photos and videos stop uploading. And it does not make the library itself smaller: every duplicate and long video still counts against iCloud at full size.

Step 1 of 6Optimize keeps the full-size originals in iCloud. To make the library itself smaller, start on the Clean tab: Videos take 27.4 GB. Tap it.

Step 2 of 6The largest videos come first, each with its size. Tap the ones to compress.

Step 3 of 6Three picked, 19.7 GB in all: compressing them saves about 9.85 GB. Tap Compress Selected.

Step 4 of 6At Medium, 19.7 GB becomes about 9.85 GB, and each original is replaced by its smaller version. A video stored in iCloud is downloaded first. Tap Compress 3 videos.

Step 5 of 6It compresses on your iPhone. Nothing is replaced until every video is ready; then iOS asks you to confirm once.

Step 6 of 63 videos compressed: the library is 9.85 GB smaller. The originals wait in Recently Deleted, and the space comes back when you empty it, or after 30 days.

Phone Cleaner checks the photos that are on your iPhone. Photos that are in iCloud only are checked when they come back to the iPhone, and a video stored in iCloud is downloaded before it is compressed.

How to turn it off and download the originals

1. Open Settings, tap your name, then tap iCloud.
2. Tap Photos. On iOS 27 or later, tap iPhone Storage.
3. Choose Download and Keep Originals.