Every slideshow starts the same way: you add photos and videos to it. SlideFlow gives you two ways to do that—from your Apple Photos library, or from files on your Mac, in the Files app, on an external drive, or in iCloud Drive.
Most of the time the choice makes itself. The picture is wherever it happens to be, you add it from there, and the slideshow plays. But the two sources behave differently once the slideshow exists. Played or exported, the slideshow looks the same either way; what differs is what it costs you, and what happens to it later: a slideshow that takes gigabytes of iCloud storage while another takes almost none, a photo you edited in Photos that updated itself inside a slideshow you made months ago, or a folder of holiday videos that plays perfectly even after you unplugged the drive they came from.
In short: use your Photos library whenever the media is already there. It costs almost no storage, it unlocks everything SlideFlow can do automatically—Moments, date ranges, albums, favorites—and edits you make in Photos flow straight into your slideshows. Use files for anything that isn’t in your library: they’re copied into the slideshow, which costs real storage but makes the slideshow’s photos and videos completely self-contained. And you can even mix both in one slideshow without thinking about it. If your photos don’t live in Photos in the first place—Lightroom, Capture One, folders on a drive—then files are simply your route, and most of the trade-off below doesn’t apply to you.
| Photos Library | Files | |
|---|---|---|
| Stored in the slideshow as | A reference | A copy |
| Extra storage used | Almost none | Full size of the media |
| Sync to your other devices | Usually fast | Slower for large media |
| Moments, date ranges, albums | Yes | No |
| Edits made later in Photos | Followed automatically | Not followed |
| If the original is deleted | The item goes missing | Slideshow unaffected |
| Requires Photos library access | Yes | No |
| Media self-contained in slideshow | No | Yes |
| Can mix both in one slideshow | Yes | Yes |
Two ways to add photos and videos
Both live behind the same Add button at the bottom of a slideshow.
Select Files… opens the standard file picker—Finder on Mac, the Files app on iPhone and iPad—so you can reach anything the system can: your Pictures folder, an external drive or SD card reader, iCloud Drive, Dropbox, a shared network volume. Any image or video file your device can read is accepted. The app tells you the important part right there in the menu, under the command: Files are copied, taking up your storage.
Add from Photos works with your Apple Photos library. Select… inside it opens the system photo picker for choosing items by hand, and the rest of the submenu is the automatic route—by date range, from one of your albums, or from a Photos smart album, with switches for including photos, including videos, and including only your favorites.
On Mac there’s a convenient third way in: drag the files straight onto the slideshow. Drop a selection from Finder onto the media grid and they’re added exactly as if you’d picked them with Select Files….
Adding files takes a moment—they’re being copied—so SlideFlow shows a progress sheet while it works, with a Cancel button. Cancelling stops the rest; anything already imported stays in the slideshow.
The one difference everything else follows from
Photos library media is referenced by SlideFlow; file-based media is copied into the slideshow.
When you add an item from your Photos library, SlideFlow stores a reference to it—a pointer into your library. The photo stays where it is, owned by Photos, and the slideshow just knows how to find it.
When you add a file, SlideFlow copies it into the slideshow. From that moment the copy belongs to the slideshow, and SlideFlow no longer uses the original file.
Everything below—storage, sync, editing, deleting, permissions—follows from that one distinction.
Using your Photos library
Almost no storage, and quick sync
A reference takes very little storage compared with a full-resolution media file. A copy is a few megabytes, or even gigabytes for large videos.
That means a slideshow built from your library uses very little storage—a 300-photo slideshow of a summer holiday is not significantly bigger than a 10-photo one. The slideshow itself can sync quickly because SlideFlow doesn’t have to upload another copy of the media. The photos are already stored in your Photos library, and if you use iCloud Photos, they’re already covered by the storage you’re paying for there—you aren’t paying for a second copy in SlideFlow.
Syncing slideshows across your devices covers this side in detail, including what you need to switch on and what to check when something doesn’t arrive.
Slideshows that build themselves
This is the difference most people underestimate, because it isn’t about the photos at all—it’s about not having to pick them.
With a sufficient (preferably full) library access, SlideFlow can assemble slideshows for you. Give it a date range and it creates one from the photos you took then. Point it at one of your albums or smart albums and it builds a slideshow from that. Ask for Moments and it goes through your library on its own, groups your photos into the events they naturally belong to by when and where they were taken, and names each group after its dates and place—a weekend away becomes one slideshow, a birthday dinner another. Three toggles refine any of these routes: photos only, videos only, or favorites only.
None of that is possible with files. A file is something you picked; SlideFlow knows nothing about when it was taken relative to anything else, whether you starred it, or which album you’d have put it in. Files are always a manual selection.
The same asymmetry shows up in small ways throughout the app. A library photo you marked as a favorite in Photos carries its star into the slideshow’s media grid; an imported file has no favorite status to show.
Edits you make in Photos show up in your slideshow
When SlideFlow loads a library photo, it asks Photos for the current version of it. So if you crop a photo, straighten it, or push the exposure in Photos—today or next year—the slideshow you made last summer plays the edited version, on every device, without you touching it.
An imported file is the opposite: it’s a snapshot of the file as it was the moment you added it. Edit the original afterwards and the slideshow keeps playing the old copy, because that copy is what the slideshow contains.
Which of those you want depends on the situation, and both are defensible. Library references mean your slideshows always show your best current version of each photo. File copies mean a slideshow you finished stays finished, immune to anything you do to your files later.
Photos that aren’t on this device are fetched when they’re needed
If you use Optimize Storage, most of your library isn’t actually on your Mac or iPhone—only small previews are, with the full-resolution originals in iCloud. SlideFlow handles this: when it needs a photo or video at full quality and only a preview is present, it asks Photos to pull the original down from iCloud.
The practical consequence is that library slideshows want a network connection the first time they play on a device that hasn’t downloaded those particular photos yet—along with iCloud Photos switched on for that library, which is what puts the photos on the other device at all. Once Photos has them, they play from local storage like anything else.
It’s also where you may notice the difference. SlideFlow loads the first few items before playback begins, so a slideshow whose opening photos are still only in iCloud takes a little longer than usual to start. After that it keeps loading ahead of what’s on screen, which normally hides the delay—but over a slow connection the slideshow can catch up with the downloads while it plays. Export works the same way, except that every item has to be fetched, so exporting a slideshow whose photos aren’t downloaded yet is slower than exporting the same one again afterwards.
There’s a stronger version of the same problem. Fetching a photo on demand only works if this device’s library knows about it in the first place—and a photo you took on your iPhone an hour ago, or anything at all on a Mac you haven’t opened in months, may not have reached it yet. Then there is nothing for SlideFlow to fetch: the item shows as failed to load, even though the slideshow itself arrived intact.
The fix isn’t in SlideFlow. Open the Photos app on that device, leave it running on Wi-Fi and on power, and give it time to finish syncing—for a library that’s badly behind, that can take hours. SlideFlow can only show what Photos has actually got. Sync troubleshooting covers this alongside the other reasons a slideshow can turn up incomplete.
Why SlideFlow recommends full Photos access
Limited access—where you hand the app a hand-picked set of photos instead of the whole library—isn’t refused: SlideFlow runs, and you can build and play slideshows from the photos you granted. But two capabilities fall away.
The first is the automatic half of the app. Moments, date ranges, albums, and smart albums all work by looking through your library, and under limited access there is almost nothing there to look through—so they come back empty, or with a handful of items.
The second is sync. The same photo is identified differently on every device, so to find the items a slideshow refers to, SlideFlow has to look them up in your library—and that lookup only runs with full access. Without it, a slideshow arriving from another device is intact, but its photos can’t be resolved on this one.
Full access is about what SlideFlow can find in your library, not about what happens to it afterwards. SlideFlow reads your photos only to show them in your slideshows, and stores references to them rather than uploading copies of its own.
What happens when you delete a photo from Photos
Deleting a photo from your library empties its slot in every slideshow that used it: there’s nothing left to point at. The item stays in the slideshow, marked as failed to load, and playback simply skips over it—the slideshow still plays, just shorter. That’s the flip side of never storing a second copy: the Photos library is the source for that media, so a slideshow can’t outlive the photos in it.
Using files from outside Photos
Media that isn’t in your library
The obvious one, and the reason the option exists. A video someone sent you, footage straight off a camera card, a graphic you made in another app, an old folder of scans you never imported into Photos—all of it goes into a slideshow directly, with no detour through the Photos app.
For some people that’s not the odd file—it’s everything they shoot. If you keep your photos in Lightroom, Capture One, or simply in folders on a drive, as many photographers do, then the Photos app holds little or nothing you’d want in a slideshow, and every route in this guide that begins with your library is beside the point. Adding files isn’t a fallback in that case; it’s simply how SlideFlow works for you, and the slideshow’s media is self-contained from then on.
Imported files are self-contained
Once a file is imported, the original is irrelevant. Delete it, rename it, move it to another folder, unplug the drive it lived on, empty your Downloads—the slideshow plays exactly the same, because it isn’t reading that file any more. It’s reading its own copy.
For a slideshow you assembled out of working files scattered across a drive, that’s a genuine relief. It’s also what makes imported media reliable across devices: the copy travels with the slideshow, so it plays on your iPad whether or not your iPad has ever seen the original.
That permanence is specific to slideshows. The Play on TV browser treats files differently again. Its Imports list, for casting files you haven’t put in a slideshow, is temporary—empty again the next time you launch the app. And on Mac it also has Folders, which it does remember between launches, but those are references to folders on that Mac rather than copies, so they never reach your other devices.
Can you use SlideFlow without Photos access?
Yes—you can skip Photos access entirely. SlideFlow offers Use Files Only when it first asks, and everything that doesn’t depend on the library keeps working: build slideshows from files, customize them, play them, cast them to your TV, export them as videos.
What you give up is the automatic half of the app—Moments, date ranges, albums, favorites filtering—and, as the app warns you at that screen, you’ll use more storage on your device and in iCloud, since every item now has to be copied.
Why imported files use more storage
The copy is a full-size copy of the original file, and you pay for it in two places: it counts against your iCloud storage quota like anything else kept in iCloud (if sync is enabled), and it takes up space on every device the slideshow reaches, because the file has to be present for the slideshow to play there.
You’re also, in most cases, storing the media twice on the same machine—once as your original file, once as the slideshow’s copy.
A handful of photos is nothing to think about. Video is a different matter: a single file runs to hundreds of megabytes or several gigabytes, depending on its length, resolution, and format, and a slideshow built from imported video can easily be the largest thing SlideFlow ever puts in your iCloud account, or on your iPhone. It’s also slow to sync, since the whole thing has to upload from one device and download on the other—and on a device the slideshow has only just reached, SlideFlow may have to wait for that copy to finish arriving before it can play.
The storage isn’t stranded, though. Remove an item from a slideshow, or delete the slideshow, and SlideFlow deletes its copy and the space comes back. Your original file is untouched either way.
One more detail worth knowing: if iCloud isn’t available when you import a file, SlideFlow keeps the copy on that device only. The slideshow works normally there—but that particular file has no route to your other devices.
Which should you use?
The rule of thumb fits in one line: if it’s in your Photos library, add it from there. If it isn’t, import the file.
Reasons to deliberately choose the Photos library:
- The media is already in your library—which, for most people, is most of the time.
- You want SlideFlow to build slideshows for you from dates, albums, or favorites.
- You care about iCloud storage, or you’re on a small plan.
- You still edit these photos, and want your slideshows to follow.
- You want the slideshow on your other devices quickly.
Reasons to deliberately choose files:
- The media simply isn’t in your library, and you don’t want to put it there.
- You don’t use the Photos app at all—your photos live in Lightroom, Capture One, or in folders.
- Your Photos library doesn’t sync between your devices.
- You want the slideshow’s media to be self-contained and immune to changes in your library.
- You’d rather not grant an app full access to your photo library.
- It’s a small number of items, or a one-off project.
If your Photos library doesn’t sync between your devices but you want your slideshows to, importing is right even for media that could just as well be added from that library. SlideFlow’s own iCloud sync is separate from iCloud Photos, so you can have slideshows syncing perfectly well while your library stays local to one Mac. A slideshow built from that library then reaches your iPad as a set of references into a library the iPad has never seen, and nothing in it plays. Importing the files is the way out: the copies travel with the slideshow, so it arrives complete wherever it lands.
The same logic applies beyond photos and videos. An image you add as an overlay—a logo, a title card—is imported and copied into the slideshow, and so is an audio file you add as music. Music has one extra wrinkle: songs pulled from the Music app on iPhone and iPad can’t be copied at all, so they stay on the device you added them on. How music syncs covers that case.
Mixing both in one slideshow
Nothing forces you to choose per slideshow. One slideshow can hold library photos, library videos, and imported files in any combination and any order, and once they’re in, SlideFlow treats them identically.
Transitions ease an imported clip in exactly as they do a library photo. Filters restyle both. Photo duration, face-aware animations, adaptive background, and every per-item override work the same on either. Playing on a TV, and exporting to a video file, don’t distinguish between them at all.
So the source only ever affects the things covered above—storage, sync, what SlideFlow can do for you automatically, and what happens to the slideshow when the original changes. Everything downstream of adding the media is identical.
A few practical tips
- If you use Photos, put it there first when it’s staying. For media you’ll want again—a video someone sent you, footage you’ll use in several slideshows—importing it into Photos and adding it from there avoids storing another copy in each slideshow and buys you everything the library route offers. Importing the file into three slideshows makes three copies.
- Importing large photos? Downsize them first. SlideFlow loads a photo at about twice your output’s long edge, for room to zoom into it—roughly 7,700 pixels for a 4K export, 3,900 for 1080p. Anything beyond that is discarded on load, so full-resolution frames from a high-megapixel camera buy you nothing and cost you storage in every slideshow they’re in. Our iBatch on Mac and iSize on iPhone and iPad resize a whole folder of them in one go.
- Watch out for large imported videos. It’s the one case where a single slideshow can consume gigabytes. If the clip is in your Photos library, add it from there instead.
- If you use your library at all, grant full access. Limited access is a common reason a synced slideshow arrives on another device with its photos missing.
- Deleting from your library affects your slideshows. Worth remembering before a clear-out: any slideshow that referenced the photo will show a gap.
- Removing media frees the space. If a slideshow has grown large, removing imported items—or deleting the slideshow—deletes their copies too.
- To make a slideshow permanent and portable, export it. An exported video is a single file that depends on nothing: not your library, not iCloud, not SlideFlow. That’s the version to send to someone or archive.
(Note: New to SlideFlow? The step-by-step tutorials for Mac or iPhone and iPad walk you through your first slideshow in a few minutes. More questions are answered in the SlideFlow FAQ).
