Given below is an asynchronous task to load an user image from the Isolated Phone Storage and return it as a BitmapImage object.

public async Task loaduserimage()
        {
            BitmapImage bi = new BitmapImage();

            using (IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication())
            {

                if (myIsolatedStorage.FileExists("filename.extension"))
                {
                     using (IsolatedStorageFileStream fileStream = myIsolatedStorage.OpenFile("filename.extension", FileMode.Open, FileAccess.Read))
                        {
                            bi.SetSource(fileStream);

                        }
                }
                else
                {
                    MessageBox.Show("File not found");

                }

            }
            return bi;
}