Where apps hide your files
macOS keeps wallpapers in three places: the built-in pictures, the downloaded Aerial videos, and a small file recording which one you picked. Here is each path, what is really inside, and what to leave alone.
Built-in wallpapers:
/System/Library/Desktop Pictures/Downloaded Aerials and other video wallpapers:
/Library/Application Support/com.apple.idleassetsd/Customer/Your current choice (a settings file, not the pictures):
~/Library/Application Support/com.apple.wallpaper/Store/Index.plistOpen any of them with ⇧⌘G in Finder (Go > Go to Folder), or run open "/System/Library/Desktop Pictures" in Terminal. Everything here was checked on macOS Sequoia 15.6. Tahoe 26 and older releases can differ in the details, so the commands below let you confirm on your own Mac.
Most of the wallpapers listed in System Settings > Wallpaper are not full pictures in this folder at all. On the Mac checked:
| Item | What it is |
|---|---|
.heic files | Full pictures stored on the Mac. Only nine: Sonoma.heic, Radial Sky Blue.heic and the seven iMac colours such as iMac Blue.heic. |
.madesktop files | Small settings files of about 500 bytes. Each names a picture that macOS downloads when you choose it, plus a thumbnail. Most named wallpapers are this kind: Big Sur, Catalina, Monterey Graphic, Ventura Graphic, The Cliffs, Solar Gradients and 57 more. |
.wallpapers (hidden) | The newer animated wallpapers, such as Sequoia Sunrise and Sonoma, as .mov videos with still .heic versions. |
.thumbnails (hidden) | 134 small previews used by the Settings pane. |
Solid Colors | 19 plain-colour .png files. |
The whole folder came to 654 MB, of which 448 MB was the hidden .wallpapers folder. Press ⇧⌘. in Finder to show the hidden folders.
You can copy a .heic, .png or .mov out to use elsewhere, for example to drag a picture into Keynote. A .madesktop is not a picture, so copying it gives you nothing to open. You cannot add, edit or delete anything here: /System sits on the sealed, read-only system volume, and macOS replaces it with each update. Copy a file to your Desktop first, then work on the copy.
Aerials are large videos, so macOS downloads each one when you choose it in System Settings > Wallpaper or Screen Saver. They are stored under the Customer folder above, in subfolders named by quality: 4KSDR240FPS, 4KSDR, 4KHDR, 2KSDR, 2KHDR and 2KAVC. Reports describe the videos as .mov files; none had been downloaded on the Mac checked, so every quality folder was empty.
Beside those subfolders sit entries.json (the catalogue of available Aerials), resources.tar and TVIdleScreenStrings.bundle, which holds the names and descriptions shown in Settings. One level up, com.apple.idleassetsd also holds snapshots, a folder of 141 small JPEG previews, and a database, Aerial.sqlite. Do not open or edit the database.
With nothing downloaded, the whole com.apple.idleassetsd folder was 14 MB. After you pick a few Aerials it grows quickly, so check it with this read-only command:
du -sh /Library/Application\ Support/com.apple.idleassetsd/System/Library/AssetsV2/com_apple_MobileAsset_DesktopPicture/ holds the catalogue for the downloadable pictures behind the .madesktop files. On this Mac it held only one .xml file, because no such wallpaper had been downloaded. Downloaded pictures are likely to appear here as asset folders, but that could not be confirmed./System/Library/Screen Savers/ and the newer screen saver extensions are separate from wallpapers, though Aerials serve both.To use a built-in wallpaper as an image, copy its .heic from /System/Library/Desktop Pictures to a folder you own. For one of the .madesktop wallpapers, choose it in Settings so it downloads, then take a screenshot of an empty desktop with ⇧⌘3. That also works for whatever wallpaper you have now.
Wallpapers rarely matter for disk space, with one exception: downloaded Aerials. On Sequoia, the Wallpaper settings pane includes a Remove Download command for downloaded wallpapers. It appears in the pane's interface text on this Mac but could not be tried, since nothing had been downloaded. Control-click a downloaded wallpaper or Aerial in System Settings > Wallpaper to see whether it is offered.
The files under idleassetsd are owned by the system, so Finder asks for an administrator password to change them. Apple does not document deleting them by hand, so avoid it. General > Storage in System Settings shows how much space system data takes overall.
Never delete anything in /System/Library. It is protected for a reason, and a damaged system volume means a reinstall.
Migration Assistant moves your user settings, but do not count on downloaded Aerials arriving with them: expect them to download again when you choose them. Pictures you chose from your own folders need to come across with your files, or the wallpaper setting will point at nothing.
Spotlight's index does contain the built-in wallpapers, but it marks them as system files (mdls shows kMDItemSupportFileType = MDSystemFile), which ordinary Spotlight and Finder searches leave out. Everywhere does not hide them: typing Sonoma or iMac Blue brings up the .heic straight away, Sequoia Sunrise finds the hidden video, and ⌘Y previews the picture before you copy it. It searches names only, so search for the wallpaper's name as Settings shows it.
The built-in ones are in /System/Library/Desktop Pictures/, though most there are small .madesktop files whose picture downloads when you choose it. Downloaded Aerials go to /Library/Application Support/com.apple.idleassetsd/Customer/.
In /Library/Application Support/com.apple.idleassetsd/Customer/, in quality-named subfolders such as 4KSDR240FPS and 2KHDR. A subfolder stays empty until you download an Aerial.
No. That folder is on the read-only system volume and macOS replaces it on update. Copy files out to use them, and do not try to remove them.
In ~/Library/Application Support/com.apple.wallpaper/Store/Index.plist. It is a settings file that points to the picture, not a copy of it.
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Version 2.20.3 · macOS 13+ · 4.7 MB · notarised