How to save image to custom album?

Latest Swift 3.0 syntax. :)

import Foundation
import Photos


class CustomPhotoAlbum: NSObject {
    static let albumName = "Album Name"
    static let sharedInstance = CustomPhotoAlbum()

    var assetCollection: PHAssetCollection!

    override init() {
        super.init()

        if let assetCollection = fetchAssetCollectionForAlbum() {
            self.assetCollection = assetCollection
            return
        }

        if PHPhotoLibrary.authorizationStatus() != PHAuthorizationStatus.authorized {
            PHPhotoLibrary.requestAuthorization({ (status: PHAuthorizationStatus) -> Void in
                ()
            })
        }

        if PHPhotoLibrary.authorizationStatus() == PHAuthorizationStatus.authorized {
            self.createAlbum()
        } else {
            PHPhotoLibrary.requestAuthorization(requestAuthorizationHandler)
        }
    }

    func requestAuthorizationHandler(status: PHAuthorizationStatus) {
        if PHPhotoLibrary.authorizationStatus() == PHAuthorizationStatus.authorized {
            // ideally this ensures the creation of the photo album even if authorization wasn't prompted till after init was done
            print("trying again to create the album")
            self.createAlbum()
        } else {
            print("should really prompt the user to let them know it's failed")
        }
    }

    func createAlbum() {
        PHPhotoLibrary.shared().performChanges({
            PHAssetCollectionChangeRequest.creationRequestForAssetCollection(withTitle: CustomPhotoAlbum.albumName)   // create an asset collection with the album name
        }) { success, error in
            if success {
                self.assetCollection = self.fetchAssetCollectionForAlbum()
            } else {
                print("error \(error)")
            }
        }
    }

    func fetchAssetCollectionForAlbum() -> PHAssetCollection? {
        let fetchOptions = PHFetchOptions()
        fetchOptions.predicate = NSPredicate(format: "title = %@", CustomPhotoAlbum.albumName)
        let collection = PHAssetCollection.fetchAssetCollections(with: .album, subtype: .any, options: fetchOptions)

        if let _: AnyObject = collection.firstObject {
            return collection.firstObject
        }
        return nil
    }

    func save(image: UIImage) {
        if assetCollection == nil {
            return                          // if there was an error upstream, skip the save
        }

        PHPhotoLibrary.shared().performChanges({
            let assetChangeRequest = PHAssetChangeRequest.creationRequestForAsset(from: image)
            let assetPlaceHolder = assetChangeRequest.placeholderForCreatedAsset
            let albumChangeRequest = PHAssetCollectionChangeRequest(for: self.assetCollection)
            let enumeration: NSArray = [assetPlaceHolder!]
            albumChangeRequest!.addAssets(enumeration)

        }, completionHandler: nil)
    }
}

I came up with this singleton class to handle it:

import Photos

class CustomPhotoAlbum {

    static let albumName = "Flashpod"
    static let sharedInstance = CustomPhotoAlbum()

    var assetCollection: PHAssetCollection!

    init() {

        func fetchAssetCollectionForAlbum() -> PHAssetCollection! {

            let fetchOptions = PHFetchOptions()
            fetchOptions.predicate = NSPredicate(format: "title = %@", CustomPhotoAlbum.albumName)
            let collection = PHAssetCollection.fetchAssetCollectionsWithType(.Album, subtype: .Any, options: fetchOptions)

            if let firstObject: AnyObject = collection.firstObject {
                return collection.firstObject as! PHAssetCollection
            }

            return nil
        }

        if let assetCollection = fetchAssetCollectionForAlbum() {
            self.assetCollection = assetCollection
            return
        }

        PHPhotoLibrary.sharedPhotoLibrary().performChanges({
            PHAssetCollectionChangeRequest.creationRequestForAssetCollectionWithTitle(CustomPhotoAlbum.albumName)
        }) { success, _ in
            if success {
                self.assetCollection = fetchAssetCollectionForAlbum()
            }
        }
    }

    func saveImage(image: UIImage) {

        if assetCollection == nil {
            return   // If there was an error upstream, skip the save.
        }

        PHPhotoLibrary.sharedPhotoLibrary().performChanges({
            let assetChangeRequest = PHAssetChangeRequest.creationRequestForAssetFromImage(image)
            let assetPlaceholder = assetChangeRequest.placeholderForCreatedAsset
            let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: self.assetCollection)
            albumChangeRequest.addAssets([assetPlaceholder])
        }, completionHandler: nil)
    }


}

When you first instantiate the class, the custom album will be created if it doesn't already exist. You can save an image like this:

CustomPhotoAlbum.sharedInstance.saveImage(image)

NOTE: The CustomPhotoAlbum class assumes the app already has permission to access the Photo Library. Dealing with the permissions is a bit outside the scope of this question/answer. So make sure PHPhotoLibrary.authorizationStatus() == .Authorize before you use it. And request authorization if necessary.

This is an updated version, works in Swift 2.1, and avoids the bug where the album is not created and images are not saved on the first launch (when authorization to write to the photo library is first requested/granted).

class CustomPhotoAlbum: NSObject {
    static let albumName = "Name of Custom Album"
    static let sharedInstance = CustomPhotoAlbum()

    var assetCollection: PHAssetCollection!

    override init() {
        super.init()

        if let assetCollection = fetchAssetCollectionForAlbum() {
            self.assetCollection = assetCollection
            return
        }

        if PHPhotoLibrary.authorizationStatus() != PHAuthorizationStatus.Authorized {
            PHPhotoLibrary.requestAuthorization({ (status: PHAuthorizationStatus) -> Void in
                status
            })
        }

        if PHPhotoLibrary.authorizationStatus() == PHAuthorizationStatus.Authorized {
            self.createAlbum()
        } else {
            PHPhotoLibrary.requestAuthorization(requestAuthorizationHandler)
        }
    }

    func requestAuthorizationHandler(status: PHAuthorizationStatus) {
        if PHPhotoLibrary.authorizationStatus() == PHAuthorizationStatus.Authorized {
            // ideally this ensures the creation of the photo album even if authorization wasn't prompted till after init was done
            print("trying again to create the album")
            self.createAlbum()
        } else {
            print("should really prompt the user to let them know it's failed")
        }
    }

    func createAlbum() {
        PHPhotoLibrary.sharedPhotoLibrary().performChanges({
        PHAssetCollectionChangeRequest.creationRequestForAssetCollectionWithTitle(CustomPhotoAlbum.albumName)   // create an asset collection with the album name
            }) { success, error in
                if success {
                    self.assetCollection = self.fetchAssetCollectionForAlbum()
                } else {
                    print("error \(error)")
                }
        }
    }

    func fetchAssetCollectionForAlbum() -> PHAssetCollection! {
        let fetchOptions = PHFetchOptions()
        fetchOptions.predicate = NSPredicate(format: "title = %@", CustomPhotoAlbum.albumName)
        let collection = PHAssetCollection.fetchAssetCollectionsWithType(.Album, subtype: .Any, options: fetchOptions)

        if let _: AnyObject = collection.firstObject {
            return collection.firstObject as! PHAssetCollection
        }        
        return nil
    }

    func saveImage(image: UIImage, metadata: NSDictionary) {
        if assetCollection == nil {
            return                          // if there was an error upstream, skip the save
        }

        PHPhotoLibrary.sharedPhotoLibrary().performChanges({                                                                    
            let assetChangeRequest = PHAssetChangeRequest.creationRequestForAssetFromImage(image)                   
            let assetPlaceHolder = assetChangeRequest.placeholderForCreatedAsset             
            let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: self.assetCollection)       
            albumChangeRequest!.addAssets([assetPlaceHolder!])                                                      
        }, completionHandler: nil)
    }
}