有时要实现BitmapImage与byte[]相互转换，这里实现两个静态方法，直接调用即可。

byte[]转换为BitmapImage：

public static BitmapImage ByteArrayToBitmapImage(byte[] byteArray)
{
    BitmapImage bmp = null; try
    {
        bmp = new BitmapImage();
        bmp.BeginInit();
        bmp.StreamSource = new MemoryStream(byteArray);
        bmp.EndInit();
    }
    catch
    {
        bmp = null;
    } return bmp;
}

BitmapImage转换为byte[]：

public static byte[] BitmapImageToByteArray(BitmapImage bmp)
{
    byte[] byteArray = null; try
    {
        Stream sMarket = bmp.StreamSource; if (sMarket != null && sMarket.Length > 0)
        {
            //很重要，因为Position经常位于Stream的末尾，导致下面读取到的长度为0。
            sMarket.Position = 0; using (BinaryReader br = new BinaryReader(sMarket))
            {
                byteArray = br.ReadBytes((int)sMarket.Length);
            }
        }
    }
    catch
    {
        //other exception handling
    } return byteArray;
}