Guides

What "Optimize iPhone Storage" Actually Does to Your Photos

Updated October 29, 2026 · Written for iOS 26

If you use iCloud Photos, there's a setting that can save you a lot of space on your iPhone: Optimize iPhone Storage. Here's what it does and what it doesn't.

Where to find it

Open Settings > Apps > Photos (on older iOS versions, Settings > Photos). With iCloud Photos turned on, you'll see two options:

• Optimize iPhone Storage
• Download and Keep Originals

What Optimize does

Your full-quality photos and videos are stored in iCloud. When your iPhone starts running low on space, it replaces the originals on the phone with smaller, device-sized versions. When you open a photo, the original downloads from iCloud.

Your originals are not deleted or compressed. They're kept in full in iCloud.

What it doesn't do

• It doesn't free iCloud space. Your iCloud still holds every original at full size.
• It doesn't work without iCloud Photos. If iCloud Photos is off, the setting isn't there.
• It doesn't make deleting photos pointless. Deleting a photo still frees iCloud space, and some space on the phone.

When to use Download and Keep Originals instead

• You often edit photos or videos without an internet connection.
• You want a full copy on the phone, for example before switching iCloud off.
• Your iPhone has plenty of free space anyway.

The trade-off

With Optimize on, opening an older photo can take a second while it downloads, and won't work offline if it hasn't been downloaded. For most people, that's a fair price for getting back tens of gigabytes.

If your iPhone is still full

Optimize only kicks in as space runs low, and it can't help with apps, Messages or System Data. For the rest, see iPhone Storage Full? What to Delete First.