Skillshub axiom-photo-library
PHPicker, PhotosPicker, photo selection, limited library access, presentLimitedLibraryPicker, save to camera roll, PHPhotoLibrary, PHAssetCreationRequest, Transferable, PhotosPickerItem, photo permissions
git clone https://github.com/ComeOnOliver/skillshub
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skills/CharlesWiltgen/Axiom/axiom-photo-library/SKILL.mdPhoto Library Access with PhotoKit
Guides you through photo picking, limited library handling, and saving photos to the camera roll using privacy-forward patterns.
When to Use This Skill
Use when you need to:
- ☑ Let users select photos from their library
- ☑ Handle limited photo library access
- ☑ Save photos/videos to the camera roll
- ☑ Choose between PHPicker and PhotosPicker
- ☑ Load images from PhotosPickerItem
- ☑ Observe photo library changes
- ☑ Request appropriate permission level
Example Prompts
"How do I let users pick photos in SwiftUI?" "User says they can't see their photos" "How do I save a photo to the camera roll?" "What's the difference between PHPicker and PhotosPicker?" "How do I handle limited photo access?" "User granted limited access but can't see photos" "How do I load an image from PhotosPickerItem?"
Red Flags
Signs you're making this harder than it needs to be:
- ❌ Using UIImagePickerController (deprecated for photo selection)
- ❌ Requesting full library access when picker suffices (privacy violation)
- ❌ Ignoring
authorization status (users can't expand selection).limited - ❌ Not handling Transferable loading failures (crashes on large photos)
- ❌ Synchronously loading images from picker results (blocks UI)
- ❌ Using PhotoKit APIs when you only need to pick photos (over-engineering)
- ❌ Assuming
after user grants access (could be.authorized
).limited
Mandatory First Steps
Before implementing photo library features:
1. Choose Your Approach
What do you need? ┌─ User picks photos (no library browsing)? │ ├─ SwiftUI app → PhotosPicker (iOS 16+) │ └─ UIKit app → PHPickerViewController (iOS 14+) │ └─ NO library permission needed! Picker handles it. │ ├─ Display user's full photo library (gallery UI)? │ └─ Requires PHPhotoLibrary authorization │ └─ Request .readWrite for browsing │ └─ Handle .limited status with presentLimitedLibraryPicker │ ├─ Save photos to camera roll? │ └─ Requires PHPhotoLibrary authorization │ └─ Request .addOnly (minimal) or .readWrite │ └─ Just capture with camera? └─ Don't use PhotoKit - see camera-capture skill
2. Understand Permission Levels
| Level | What It Allows | Request Method |
|---|---|---|
| No permission | User picks via system picker | PHPicker/PhotosPicker (automatic) |
| Save to camera roll only | |
| User-selected subset only | User chooses in system UI |
| Full library access | |
Key insight: PHPicker and PhotosPicker require NO permission. The system handles privacy.
3. Info.plist Keys
<!-- Required for any PhotoKit access --> <key>NSPhotoLibraryUsageDescription</key> <string>Access your photos to share them</string> <!-- Required if saving photos --> <key>NSPhotoLibraryAddUsageDescription</key> <string>Save photos to your library</string>
Core Patterns
Pattern 1: SwiftUI PhotosPicker (iOS 16+)
Use case: Let users select photos in a SwiftUI app.
import SwiftUI import PhotosUI struct ContentView: View { @State private var selectedItem: PhotosPickerItem? @State private var selectedImage: Image? var body: some View { VStack { PhotosPicker( selection: $selectedItem, matching: .images // Filter to images only ) { Label("Select Photo", systemImage: "photo") } if let image = selectedImage { image .resizable() .scaledToFit() } } .onChange(of: selectedItem) { _, newItem in Task { await loadImage(from: newItem) } } } private func loadImage(from item: PhotosPickerItem?) async { guard let item else { selectedImage = nil return } // Load as Data first (more reliable than Image) if let data = try? await item.loadTransferable(type: Data.self), let uiImage = UIImage(data: data) { selectedImage = Image(uiImage: uiImage) } } }
Multi-selection:
@State private var selectedItems: [PhotosPickerItem] = [] PhotosPicker( selection: $selectedItems, maxSelectionCount: 5, matching: .images ) { Text("Select Photos") }
Advanced Filters (iOS 15+/16+)
// Screenshots only matching: .screenshots // Screen recordings only matching: .screenRecordings // Slo-mo videos matching: .sloMoVideos // Cinematic videos (iOS 16+) matching: .cinematicVideos // Depth effect photos matching: .depthEffectPhotos // Bursts matching: .bursts // Compound filters with .any, .all, .not // Videos AND Live Photos matching: .any(of: [.videos, .livePhotos]) // All images EXCEPT screenshots matching: .all(of: [.images, .not(.screenshots)]) // All images EXCEPT screenshots AND panoramas matching: .all(of: [.images, .not(.any(of: [.screenshots, .panoramas]))])
Cost: 15 min implementation, no permissions required
Pattern 1b: Embedded PhotosPicker (iOS 17+)
Use case: Embed picker inline in your UI instead of presenting as sheet.
import SwiftUI import PhotosUI struct EmbeddedPickerView: View { @State private var selectedItems: [PhotosPickerItem] = [] var body: some View { VStack { // Your content above picker SelectedPhotosGrid(items: selectedItems) // Embedded picker fills available space PhotosPicker( selection: $selectedItems, maxSelectionCount: 10, selectionBehavior: .continuous, // Live updates as user taps matching: .images ) { // Label is ignored for inline style Text("Select") } .photosPickerStyle(.inline) // Embed instead of present .photosPickerDisabledCapabilities([.selectionActions]) // Hide Add/Cancel buttons .photosPickerAccessoryVisibility(.hidden, edges: .all) // Hide nav/toolbar .frame(height: 300) // Control picker height .ignoresSafeArea(.container, edges: .bottom) // Extend to bottom edge } } }
Picker Styles:
| Style | Description |
|---|---|
| Default modal sheet |
| Embedded in your view hierarchy |
| Single row, minimal vertical space |
Customization modifiers:
// Hide navigation/toolbar accessories .photosPickerAccessoryVisibility(.hidden, edges: .all) .photosPickerAccessoryVisibility(.hidden, edges: .top) // Just navigation bar .photosPickerAccessoryVisibility(.hidden, edges: .bottom) // Just toolbar // Disable capabilities (hides UI for them) .photosPickerDisabledCapabilities([.search]) // Hide search .photosPickerDisabledCapabilities([.collectionNavigation]) // Hide albums .photosPickerDisabledCapabilities([.stagingArea]) // Hide selection review .photosPickerDisabledCapabilities([.selectionActions]) // Hide Add/Cancel // Continuous selection for live updates selectionBehavior: .continuous
Privacy note: First time an embedded picker appears, iOS shows an onboarding UI explaining your app can only access selected photos. A privacy badge indicates the picker is out-of-process.
Pattern 2: UIKit PHPickerViewController (iOS 14+)
Use case: Photo selection in UIKit apps.
import PhotosUI class PhotoPickerViewController: UIViewController, PHPickerViewControllerDelegate { func showPicker() { var config = PHPickerConfiguration() config.selectionLimit = 1 // 0 = unlimited config.filter = .images // or .videos, .any(of: [.images, .videos]) let picker = PHPickerViewController(configuration: config) picker.delegate = self present(picker, animated: true) } func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) { picker.dismiss(animated: true) guard let result = results.first else { return } // Load image asynchronously result.itemProvider.loadObject(ofClass: UIImage.self) { [weak self] object, error in guard let image = object as? UIImage else { return } DispatchQueue.main.async { self?.displayImage(image) } } } }
Filter options:
// Images only config.filter = .images // Videos only config.filter = .videos // Live Photos only config.filter = .livePhotos // Images and videos config.filter = .any(of: [.images, .videos]) // Exclude screenshots (iOS 15+) config.filter = .all(of: [.images, .not(.screenshots)]) // iOS 16+ filters config.filter = .cinematicVideos config.filter = .depthEffectPhotos config.filter = .bursts
UIKit Embedded Picker (iOS 17+)
// Configure for embedded use var config = PHPickerConfiguration() config.selection = .continuous // Live updates instead of waiting for Add button config.mode = .compact // Single row layout (optional) config.selectionLimit = 10 // Hide accessories config.edgesWithoutContentMargins = .all // No margins around picker // Disable capabilities config.disabledCapabilities = [.search, .selectionActions] let picker = PHPickerViewController(configuration: config) picker.delegate = self // Add as child view controller (required for embedded) addChild(picker) containerView.addSubview(picker.view) picker.view.frame = containerView.bounds picker.didMove(toParent: self)
Updating picker while displayed (iOS 17+):
// Deselect assets by their identifiers picker.deselectAssets(withIdentifiers: ["assetID1", "assetID2"]) // Reorder assets in selection picker.moveAsset(withIdentifier: "assetID", afterAssetWithIdentifier: "otherID")
Cost: 20 min implementation, no permissions required
Pattern 2b: Options Menu & HDR Support (iOS 17+)
The picker now shows an Options menu letting users choose to strip location metadata from photos. This works automatically with PhotosPicker and PHPicker.
Preserving HDR content:
By default, picker may transcode to JPEG, losing HDR data. To receive original format:
// SwiftUI - Use .current encoding to preserve HDR PhotosPicker( selection: $selectedItems, matching: .images, preferredItemEncoding: .current // Don't transcode ) { ... } // Loading with original format preservation struct HDRImage: Transferable { let data: Data static var transferRepresentation: some TransferRepresentation { DataRepresentation(importedContentType: .image) { data in HDRImage(data: data) } } } // Request .image content type (generic) not .jpeg (specific) let result = try await item.loadTransferable(type: HDRImage.self)
UIKit equivalent:
var config = PHPickerConfiguration() config.preferredAssetRepresentationMode = .current // Don't transcode
Cinematic mode videos: Picker returns rendered version with depth effects baked in. To get original with decision points, use PhotoKit with library access instead.
Pattern 3: Handling Limited Library Access
Use case: User granted limited access; let them add more photos.
Suppressing automatic prompt (iOS 14+):
By default, iOS shows "Select More Photos" prompt when
.limited is detected. To handle it yourself:
<!-- Info.plist - Add this to handle limited access UI yourself --> <key>PHPhotoLibraryPreventAutomaticLimitedAccessAlert</key> <true/>
Manual limited access handling:
import Photos class PhotoLibraryManager { func checkAndRequestAccess() async -> PHAuthorizationStatus { let status = PHPhotoLibrary.authorizationStatus(for: .readWrite) switch status { case .notDetermined: return await PHPhotoLibrary.requestAuthorization(for: .readWrite) case .limited: // User granted limited access - show UI to expand await presentLimitedLibraryPicker() return .limited case .authorized: return .authorized case .denied, .restricted: return status @unknown default: return status } } @MainActor func presentLimitedLibraryPicker() { guard let windowScene = UIApplication.shared.connectedScenes .first(where: { $0.activationState == .foregroundActive }) as? UIWindowScene, let rootVC = windowScene.windows.first?.rootViewController else { return } PHPhotoLibrary.shared().presentLimitedLibraryPicker(from: rootVC) } }
Observe limited selection changes:
// Register for changes PHPhotoLibrary.shared().register(self) // In delegate func photoLibraryDidChange(_ changeInstance: PHChange) { // User may have modified their limited selection // Refresh your photo grid }
Cost: 30 min implementation
Pattern 4: Saving Photos to Camera Roll
Use case: Save captured or edited photos.
import Photos func saveImageToLibrary(_ image: UIImage) async throws { // Request add-only permission (minimal access) let status = await PHPhotoLibrary.requestAuthorization(for: .addOnly) guard status == .authorized || status == .limited else { throw PhotoError.permissionDenied } try await PHPhotoLibrary.shared().performChanges { PHAssetCreationRequest.creationRequestForAsset(from: image) } } // With metadata preservation func savePhotoData(_ data: Data, metadata: [String: Any]? = nil) async throws { try await PHPhotoLibrary.shared().performChanges { let request = PHAssetCreationRequest.forAsset() // Write data to temp file for addResource let tempURL = FileManager.default.temporaryDirectory .appendingPathComponent(UUID().uuidString) .appendingPathExtension("jpg") try? data.write(to: tempURL) request.addResource(with: .photo, fileURL: tempURL, options: nil) } }
Cost: 15 min implementation
Pattern 5: Loading Images from PhotosPickerItem
Use case: Properly handle async image loading with error handling.
The problem: Default
Image Transferable only supports PNG. Most photos are JPEG/HEIF.
// Custom Transferable for any image format struct TransferableImage: Transferable { let image: UIImage static var transferRepresentation: some TransferRepresentation { DataRepresentation(importedContentType: .image) { data in guard let image = UIImage(data: data) else { throw TransferError.importFailed } return TransferableImage(image: image) } } enum TransferError: Error { case importFailed } } // Usage func loadImage(from item: PhotosPickerItem) async -> UIImage? { do { let result = try await item.loadTransferable(type: TransferableImage.self) return result?.image } catch { print("Failed to load image: \(error)") return nil } }
Loading with progress:
func loadImageWithProgress(from item: PhotosPickerItem) async -> UIImage? { let progress = Progress() return await withCheckedContinuation { continuation in _ = item.loadTransferable(type: TransferableImage.self) { result in switch result { case .success(let transferable): continuation.resume(returning: transferable?.image) case .failure: continuation.resume(returning: nil) } } } }
Cost: 20 min implementation
Pattern 6: Observing Photo Library Changes
Use case: Keep your gallery UI in sync with Photos app.
import Photos class PhotoGalleryViewModel: NSObject, ObservableObject, PHPhotoLibraryChangeObserver { @Published var photos: [PHAsset] = [] private var fetchResult: PHFetchResult<PHAsset>? override init() { super.init() PHPhotoLibrary.shared().register(self) fetchPhotos() } deinit { PHPhotoLibrary.shared().unregisterChangeObserver(self) } func fetchPhotos() { let options = PHFetchOptions() options.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)] fetchResult = PHAsset.fetchAssets(with: .image, options: options) photos = fetchResult?.objects(at: IndexSet(0..<(fetchResult?.count ?? 0))) ?? [] } func photoLibraryDidChange(_ changeInstance: PHChange) { guard let fetchResult = fetchResult, let changes = changeInstance.changeDetails(for: fetchResult) else { return } DispatchQueue.main.async { self.fetchResult = changes.fetchResultAfterChanges self.photos = changes.fetchResultAfterChanges.objects(at: IndexSet(0..<changes.fetchResultAfterChanges.count) ) } } }
Cost: 30 min implementation
Anti-Patterns
Anti-Pattern 1: Requesting Full Access for Photo Picking
Wrong:
// Over-requesting - picker doesn't need this! let status = await PHPhotoLibrary.requestAuthorization(for: .readWrite) if status == .authorized { showPhotoPicker() }
Right:
// Just show the picker - no permission needed PhotosPicker(selection: $item, matching: .images) { Text("Select Photo") }
Why it matters: PHPicker and PhotosPicker handle privacy automatically. Requesting library access when you only need to pick photos is a privacy violation and may cause App Store rejection.
Anti-Pattern 2: Ignoring Limited Status
Wrong:
let status = PHPhotoLibrary.authorizationStatus(for: .readWrite) if status == .authorized { showGallery() } else { showPermissionDenied() // Wrong! .limited is valid }
Right:
let status = PHPhotoLibrary.authorizationStatus(for: .readWrite) switch status { case .authorized: showGallery() case .limited: showGallery() // Works with limited selection showLimitedBanner() // Explain to user case .denied, .restricted: showPermissionDenied() case .notDetermined: requestAccess() @unknown default: break }
Why it matters: iOS 14+ users can grant limited access. Treating it as denied frustrates users.
Anti-Pattern 3: Synchronous Image Loading
Wrong:
// Blocks UI thread let data = try! selectedItem.loadTransferable(type: Data.self)
Right:
Task { if let data = try? await selectedItem.loadTransferable(type: Data.self) { // Use data } }
Why it matters: Large photos (RAW, panoramas) take seconds to load. Blocking UI causes ANR.
Anti-Pattern 4: Using UIImagePickerController for Photo Selection
Wrong:
let picker = UIImagePickerController() picker.sourceType = .photoLibrary present(picker, animated: true)
Right:
var config = PHPickerConfiguration() config.filter = .images let picker = PHPickerViewController(configuration: config) present(picker, animated: true)
Why it matters: UIImagePickerController is deprecated for photo selection. PHPicker is more reliable, handles large assets, and provides better privacy.
Pressure Scenarios
Scenario 1: "Just Get Photo Access Working"
Context: Product wants photo import feature. You're considering requesting full library access "to be safe."
Pressure: "Users will just tap Allow anyway."
Reality: Since iOS 14, users can grant limited access. Full access request triggers additional privacy prompt. App Store Review may reject unnecessary permission requests.
Correct action:
- Use PhotosPicker or PHPicker (no permission needed)
- Only request .readWrite if building a gallery browser
- Only request .addOnly if just saving photos
Push-back template: "PHPicker works without any permission request - users can select photos directly. Requesting library access when we only need picking is a privacy violation that App Store Review may flag."
Scenario 2: "Users Say They Can't See Their Photos"
Context: Support tickets about "no photos available" even though user granted access.
Pressure: "Just ask for full access again."
Reality: User likely granted
.limited access and selected 0 photos initially.
Correct action:
- Check for
status.limited - Show
to let user add photospresentLimitedLibraryPicker() - Explain in UI: "Tap here to add more photos"
Push-back template: "The user has limited access - they need to expand their selection. I'll add a button that opens the limited library picker so they can add more photos."
Scenario 3: "Photo Loads Taking Forever"
Context: Users complain photo picker is slow to display selected images.
Pressure: "Can you cache or preload somehow?"
Reality: Large photos (RAW, panoramas, Live Photos) are slow to decode. Solution is UX, not caching.
Correct action:
- Show loading placeholder immediately
- Load thumbnail first, full image second
- Show progress indicator for large files
- Use async/await to avoid blocking
Push-back template: "Large photos take time to load - that's physics. I'll show a placeholder immediately and load progressively. For the picker UI, thumbnail loading is already optimized by the system."
Checklist
Before shipping photo library features:
Permission Strategy:
- ☑ Using PHPicker/PhotosPicker for simple selection (no permission needed)
- ☑ Only requesting .readWrite if building gallery UI
- ☑ Only requesting .addOnly if only saving photos
- ☑ Info.plist usage descriptions present
Limited Library:
- ☑ Handling
status (not treating as denied).limited - ☑ Offering
for users to add photospresentLimitedLibraryPicker() - ☑ UI explains limited access to users
Image Loading:
- ☑ All loading is async (no UI blocking)
- ☑ Custom Transferable handles JPEG/HEIF (not just PNG)
- ☑ Error handling for failed loads
- ☑ Loading indicator for large files
Saving Photos:
- ☑ Using .addOnly when full access not needed
- ☑ Using performChanges for atomic operations
- ☑ Handling save failures gracefully
Photo Library Changes:
- ☑ Registered as PHPhotoLibraryChangeObserver if displaying library
- ☑ Updating UI on main thread after changes
- ☑ Unregistering observer in deinit
Resources
WWDC: 2020-10652, 2020-10641, 2022-10023, 2023-10107
Docs: /photosui/phpickerviewcontroller, /photosui/photospicker, /photos/phphotolibrary
Skills: axiom-photo-library-ref, axiom-camera-capture