WPF中bitmapimage与byte[]格式相互转换

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;
}