Optimize iPhone Storage or Download and Keep Originals?
Optimize iPhone Storage keeps full-size videos in iCloud and swaps in smaller copies when the phone needs room. Download and Keep Originals keeps full-size files on the phone too, so it takes more space. Neither setting lowers your iCloud use.
On this page
- The short answer
- Where to find the two settings
- What Optimize iPhone Storage does to your videos
- What Download and Keep Originals does to your videos
- The two settings side by side
- Does either setting change your iCloud use?
- What happens when you open a 4K video in iCloud
- Why Emptie skips Cloud-only Videos
- Why Optimize iPhone Storage isn’t working
- Which setting to choose
- Frequently asked questions
The short answer
With iCloud Photos on, your iPhone can keep full-size videos in two ways. Optimize iPhone Storage keeps every full-size video in iCloud and keeps smaller copies on the iPhone when it needs room. Download and Keep Originals keeps the full-size files on the iPhone as well, so it uses the most phone space. Neither setting lowers your iCloud use, because the full-size videos stay in iCloud either way.
Choose by the storage you can spare. If iCloud has room for your whole library but the phone doesn’t, Optimize iPhone Storage is the setting built for that. If the phone has room for the whole library, Download and Keep Originals keeps every video on it at full size.
Key Takeaways
- Optimize iPhone Storage keeps full-size videos in iCloud and smaller copies on your iPhone when it needs room.
- Download and Keep Originals keeps full-size videos on your iPhone too, so it takes the most phone space.
- Neither setting lowers your iCloud use. The full-size videos stay in iCloud either way.
- A video that is only in iCloud downloads when you open it, which needs a connection and free space.
- Emptie skips Cloud-only Videos, so a video has to be on your iPhone before Emptie can compress it.
Where to find the two settings
Open Settings, tap your name, tap iCloud, then tap Photos. Turn on Sync this iPhone. On iOS 27, Apple’s page adds an iPhone Storage step before the Optimize iPhone Storage option (Apple Support, Manage your photo and video storage, published 1 October 2026). We haven’t checked the iOS 26 screens against Apple’s pages, so the names may differ on your phone.
- Open iCloud PhotosSettingsYour nameiCloudPhotos
- Turn on Sync this iPhone
- Choose what the phone keepsOn iOS 27, tap iPhone Storage first, then pick one of the two.
If you searched for “optimise iPhone storage” with the UK spelling, you want this same setting. Apple spells the name “Optimize,” and this guide uses Apple’s name too.
What Optimize iPhone Storage does to your videos
Apple says that with Optimize iPhone Storage on, “full-resolution photos and videos are stored in iCloud,” and smaller copies are kept on the iPhone when it needs room (Apple Support, Manage your photo and video storage, published 1 October 2026). For a video, that means the full file goes to iCloud and the phone keeps a smaller version of it.
Apple doesn’t say how full the phone has to be before it swaps a video, or how long a video stays at full size. So you can’t tell in advance which of your videos will be swapped. Our 5-minute 4K test clip was 2.18 GB at full size. Under this setting, the phone may hold a much smaller file for that clip, and the full file stays in iCloud.
Your iPhone
Keeps room free- Smaller copies, when it needs room
- Videos you opened lately, at full size
iCloud
Holds everything- Every full-size video
What Download and Keep Originals does to your videos
With Download and Keep Originals, the full-size file of each video stays on the iPhone, as well as in iCloud. Apple’s iCloud Photos page describes the Mac version of this choice as “Download Originals to this Mac” (Apple Support, Set up and use iCloud Photos); we couldn’t find the iPhone label on Apple’s pages. Nothing is swapped for a smaller copy. The phone holds the whole library at full size, so this setting uses the most phone space of the two.
Your iPhone
Holds everything- Every full-size video
iCloud
Holds everything- Every full-size video
The arithmetic is simple. A hundred clips of 5 minutes each, at 2.18 GB apiece, take about 218 GB. That is most of a 256 GB iPhone, before iOS, apps and photos take their share.
The upside is access. Every video is on the iPhone, so you can watch any of them without a download, and Emptie can compress any of them.
The two settings side by side
| What it means for your videos | Optimize iPhone Storage | Download and Keep Originals |
|---|---|---|
| Full-size video in iCloud | Yes | Yes |
| Full-size video on the iPhone | Not for all: a smaller copy replaces it when the phone needs room | Yes, for the whole library |
| Smaller copy on the iPhone | Yes, when the phone needs room | No, the full file stays |
| Effect on your iCloud use | Same as before | Same as before |
| Phone space used | Less, and it varies | The full size of your library |
| Emptie can compress a video | Videos on the iPhone, and Cloud-only Videos are skipped | Every video, once its full file is on the iPhone |
| Opening a video that is only in iCloud | Downloads it first, which needs a connection | Not needed, once the full file is on the iPhone |
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Does either setting change your iCloud use?
No. Under both settings the full-size file stays in iCloud, so your iCloud plan fills at the same rate as before. These settings change what the phone holds, not what iCloud holds.
Compressing is the one step that can change iCloud use. In a library that syncs with iCloud Photos, Emptie’s replacement uploads the smaller copy, and the original is removed everywhere. Once the smaller copy has uploaded, it is the version that takes up iCloud space. The upload has to finish first, so check your iCloud total before and after a batch.
85% smaller
If iCloud is already full, Optimize iPhone Storage won’t help, because the full-size files need room in iCloud. Apple’s page on managing iCloud storage says that when your iCloud is over its limit, the device immediately removes any photos and videos you delete, and they can’t be recovered from Recently Deleted (Apple Support, Manage your iCloud storage on your Apple device). The Apple pages this guide cites don’t say what happens to new videos once iCloud is full, so check your total before you rely on either setting. iCloud storage full of videos shows how to check it. If your phone is full while iCloud still has room, iPhone storage full but iCloud has space explains why.
What happens when you open a 4K video in iCloud
If a video is only in iCloud, the phone keeps a preview of it. Opening the video in Photos downloads the full file first. The download needs Wi-Fi or cellular data, and it needs free space on the phone for the whole file. Our 5-minute 4K test clip is 2.18 GB, so a clip like that needs that much room and a connection that stays up while it downloads.
- You open it in PhotosThe phone has only a preview.
- The full file downloadsOver Wi-Fi or cellular data, and the connection has to stay up.
- It needs room on the phoneFree space for the whole file.
- It plays at full size
Apple’s pages this guide cites don’t say how long a downloaded video stays on the phone, so don’t count on it staying there.
Why Emptie skips Cloud-only Videos
Emptie’s Library shows each Cloud-only Video with a badge, counts them and says how much space they take. It doesn’t select them. A compressor needs the full file on the device, and Emptie is no different. There are three reasons.
- The phone has only a preview. There is no full-size file on the iPhone to re-encode.
- Emptie makes no network calls. It can’t fetch the full file from iCloud by itself.
- The space would be in iCloud. Compressing a Cloud-only Video would mostly shrink what iCloud holds. Emptie’s first release is built to free space on the phone, so it doesn’t compress these.
To use one of these videos with Emptie, put the full file on your iPhone first. Opening the video in Photos does that for one clip. Once the full file is on the phone, Emptie can consider it.
Why Optimize iPhone Storage isn’t working
If Optimize iPhone Storage doesn’t seem to free any space, check these four things.
- iCloud is full. The full-size files need room in iCloud. Open Settings, tap your name, tap iCloud, then tap Storage or Manage Account Storage. If you’re at the limit, make room or buy more storage before you expect the setting to free anything.
- The iPhone is too full. A download needs room for the whole file, so a phone with almost no free space can’t bring a large Cloud-only Video back to full size.
- The connection is weak or the phone is off Wi-Fi. Downloads and uploads both need a connection and take time. Keep the phone on Wi-Fi while a big library syncs, and on power if you can. Apple’s pages this guide cites don’t say how long a sync takes.
- Recently viewed videos are still full size. A video you opened lately can stay at full size on the phone, so the Storage number may move less than you expect.
Once iCloud has room and the phone has space, the videos on the iPhone are yours to compress. Emptie works on those without waiting for iCloud. In a synced library, though, the smaller copy still uploads to iCloud, so check your iCloud room first.
Which setting to choose
Where is there room for your whole library at full size?
- If: In iCloud, but the phone is short on spaceOptimize iPhone StorageOld clips can live in iCloud while the phone keeps smaller copies.
- If: On the iPhoneDownload and Keep OriginalsEvery video stays on the phone, ready to watch or compress without a download.
- If: Neither: iCloud is fullMake room in iCloud firstOptimize iPhone Storage needs iCloud room for the full-size files.
Either way, your iCloud total stays the same. To make the phone smaller, compress the large clips you want to keep, one at a time. How to find your biggest videos on iPhone shows how to find them, and how to free up iPhone storage without losing your videos compares the other options.
Frequently asked questions
Does Optimize iPhone Storage free up iCloud space?
No. The full-size videos stay in iCloud, so your iCloud use stays the same. The setting frees space on the iPhone only.
Does Download and Keep Originals use more iCloud space?
No. Both settings keep full-size videos in iCloud. The difference is what the iPhone holds.
Will compressing a video lower my iCloud use?
It can, in a library that syncs with iCloud Photos. The smaller copy uploads and takes the place of the original, so the video takes less iCloud space once the upload finishes. Your iCloud plan may not drop until the upload is complete and the original is gone from every device.
Why does Emptie skip some of my videos?
Emptie skips Cloud-only Videos, which have only a preview on the iPhone, because compressing needs the full file on the phone. Open the video in Photos so the full file downloads, and Emptie can consider it after that.