// Read byte[] from png file

BinaryReader binReader = new BinaryReader(File.Open(filepath, FileMode.Open));

FileInfo fileInfo = new FileInfo(filepath);

byte[] bytes = binReader.ReadBytes((int)fileInfo.Length);

binReader.Close();

// Init bitmap

BitmapImage bitmap = new BitmapImage();

bitmap.BeginInit();

//bitmap.DecodePixelWidth = Convert.ToInt32(w);

//bitmap.DecodePixelHeight = Convert.ToInt32(h);

//bitmap.CacheOption = System.Windows.Media.Imaging.BitmapCacheOption.OnLoad;

//bitmap.CreateOptions = System.Windows.Media.Imaging.BitmapCreateOptions.IgnoreImageCache;

bitmap.StreamSource = new MemoryStream(bytes);

bitmap.EndInit();