axiom-photo-library

Photo 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 .limited authorization status (users can't expand selection)
• ❌ 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 .authorized after user grants access (could be .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)
.addOnly	Save to camera roll only	requestAuthorization(for: .addOnly)
.limited	User-selected subset only	User chooses in system UI
.authorized	Full library access	requestAuthorization(for: .readWrite)

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
.presentation	Default modal sheet
.inline	Embedded in your view hierarchy
.compact	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")
``

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