How to show images within folder using collection view in swift

You can try this way.Below code is fetch the "Repost" folder from gallery and fetch all the photos of it.

 func getImages() {

    image = []
    let albumName = "Repost" //album name
    let fetchOptions = PHFetchOptions()

    var assetCollection = PHAssetCollection()
    fetchOptions.predicate = NSPredicate(format: "title = %@", albumName)
    let collection:PHFetchResult = PHAssetCollection.fetchAssetCollections(with: .album, subtype: .any, options: fetchOptions)

    if let _:AnyObject = collection.firstObject{
        //found the album
        assetCollection = collection.firstObject!
        albumFound = true
    }
    else { albumFound = false
        print("album not found")
    }

    let assets = PHAsset.fetchAssets(in: assetCollection, options: nil) as! PHFetchResult<AnyObject>

    assets.enumerateObjects({ (object, count, stop) in
        // self.cameraAssets.add(object)
        if object.mediaType == .image
        {
            self.image.append(object as! PHAsset) // for image
        }
    })

    self.image.reverse()
    self.imgcollection.reloadData()
}

Don't forgot to import photos framework. Thanks.

In case you are still struggling to figure out here is the code snippet, good luck

func saveImageToDocumentDirectory(image: UIImage ) {
    let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
    let fileName = "image001.png" // name of the image to be saved
    let fileURL = documentsDirectory.appendingPathComponent(fileName)

    if let data = UIImageJPEGRepresentation(image, 1.0),!FileManager.default.fileExists(atPath: fileURL.path) {
        do {
            try data.write(to: fileURL)
            print("file saved")
        } catch {
            print("error saving file:", error)
        }
    }
}

func loadImageFromDocumentDirectory(nameOfImage : String) -> UIImage {
    let nsDocumentDirectory = FileManager.SearchPathDirectory.documentDirectory
    let nsUserDomainMask = FileManager.SearchPathDomainMask.userDomainMask
    let paths = NSSearchPathForDirectoriesInDomains(nsDocumentDirectory, nsUserDomainMask, true)

    if let dirPath = paths.first {
        let imageURL = URL(fileURLWithPath: dirPath).appendingPathComponent(nameOfImage)
        let image    = UIImage(contentsOfFile: imageURL.path)
        return image!
    }
    return UIImage.init(named: "default.png")!
}