public async Task Save(string filename)
{
var imageProperties = ImageEncodingProperties.CreateJpeg();
ImageFile = await KnownFolders.PicturesLibrary.CreateFileAsync(
filename, CreationCollisionOption.ReplaceExisting);
await MediaDevice.CapturePhotoToStorageFileAsync(imageProperties, ImageFile);
LastPhotoSavedPath = ImageFile.Path;
}