- (void)saveImage:(UIImage *)image {
  UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil); 
}

- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {
  if (error) {
    // Fail
  } else {
    // Success
  }
}

func saveImage(_ image: UIImage) {
  UIImageWriteToSavedPhotosAlbum(image, self, #selector(image(_:didFinishSavingWithError:contextInfo:)), nil)
}

func image(_ image: UIImage, didFinishSavingWithError error: NSError?, contextInfo: AnyObject) {
  if error == nil {
    // Success
  } else {
    // Fail
  }
}

func saveImage(_ image: UIImage) {
  PHPhotoLibrary.shared().performChanges({ 
    PHAssetChangeRequest.creationRequestForAsset(from: image)
  }, completionHandler: { (success, error) in
    // NOT on main thread
    if success {
      // Success
    } else if let error = error {
      // Handle error
    }
  })
}

func saveImageData(_ data: Data) {
  if #available(iOS 9.0, *) {
    PHPhotoLibrary.shared().performChanges({
      PHAssetCreationRequest.forAsset().addResource(with: .photo, data: data, options: nil)
    }, completionHandler: { (success, error) in
      // NOT on main thread
      if success {
        // Success
      } else if let error = error {
        // Handle error
      }
    })
  } else {
    // Write image data to temp file
    let tempPath = NSTemporaryDirectory().appending("TempImageToSaveToPhoto.image")
    let tempUrl = URL(fileURLWithPath: tempPath)
    try? data.write(to: tempUrl)
    
    PHPhotoLibrary.shared().performChanges({
      PHAssetChangeRequest.creationRequestForAssetFromImage(atFileURL: tempUrl)
    }, completionHandler: { (success, error) in
      // NOT on main thread
      if success {
        // Success
      } else if let error = error {
        // Handle error
      }
      // Remove temp file
      try? FileManager.default.removeItem(at: tempUrl)
    })
  }
}

- (void)storeImage:(nullable UIImage *)image
     imageData:(nullable NSData *)imageData
      forKey:(nullable NSString *)key
      toDisk:(BOOL)toDisk
    completion:(nullable SDWebImageNoParamsBlock)completionBlock;

UIImagePickerControllerOriginalImage // 原始 UIImage
UIImagePickerControllerEditedImage // 编辑后的 UIImage
UIImagePickerControllerReferenceURL // ALAsset 的 URL

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
  picker.dismiss(animated: true, completion: nil)
  
  if let image = info[UIImagePickerControllerOriginalImage] as? UIImage {
    // Get original image
  }
  
  if let url = info[UIImagePickerControllerReferenceURL] as? URL,
    let asset = PHAsset.fetchAssets(withALAssetURLs: [url], options: nil).firstObject {
    PHImageManager.default().requestImageData(for: asset, options: nil, resultHandler: { (imageData, _, _, _) in
      if let data = imageData {
        // Get image data
      }
    })
  }
}

- (nullable id <SDWebImageOperation>)loadImageWithURL:(nullable NSURL *)url
                       options:(SDWebImageOptions)options
                       progress:(nullable SDWebImageDownloaderProgressBlock)progressBlock
                      completed:(nullable SDInternalCompletionBlock)completedBlock;

SDWebImageManager.shared().loadImage(with: url, options: SDWebImageOptions(rawValue: 0), progress: nil, completed: { [weak self] (cachedImage, imageData, error, _, _, _) in
  guard self != nil else { return }
  
  if let image = cachedImage {
    // Get image
  }
  if let data = imageData {
    // Get image data
  }
  if error != nil {
    // Handle error
  }
})

SDWebImageManager.shared().diskImageExists(for: imageUrl) { [weak self] (exist) in
  // Always on main thread
  guard self != nil else { return }
  if exist {
    // Find image data from disk
    var data: NSData?
    // Get cache key
    let key = SDWebImageManager.shared().cacheKey(for: imageUrl)
    // Get cache path
    if let path = SDImageCache.shared().defaultCachePath(forKey: key) {
      data = NSData(contentsOfFile: path)
      if data == nil {
        data = NSData(contentsOfFile: (path as NSString).deletingPathExtension)
      }
    }
    if data != nil {
      // Get image data
    } else {
      // Fail getting image data
    }
  } else {
    // No disk image
  }
}

// Get cache key
let key = SDWebImageManager.shared().cacheKey(for: imageUrl)
// Remove memory cache
SDImageCache.shared().removeImage(forKey: key, fromDisk: false, withCompletion: nil)
// Load image and data
SDWebImageManager.shared().loadImage(with: imageUrl, options: SDWebImageOptions(rawValue: 0), progress: nil) { [weak self] (_, data, _, _, _, _) in
  guard self != nil else { return }
  if data != nil {
    // Get image data
  } else {
    // Fail getting image data
  }
}