Sending blob or byte array in XML

First of all. Convert your Bitmap into ByteArray and then Convert that byte array to Base64 String format and send that Base64 String format in xml.

ByteArrayOutputStream baos = new ByteArrayOutputStream();  
bmp.compress(CompressFormat.PNG, 0 , baos); //bmp is the bitmap object   
byte[] b = baos.toByteArray(); 
String encodedImage = Base64.encodeToString(b, Base64.DEFAULT);

Now send encodedImage in your xml...

Base64 to bitmap conversion

public static Bitmap convertByteArrayToBitmap(String Base64String) 
{
    byte[] data = Base64.decode(Base64String, Base64.DEFAULT);
    Bitmap bitmap = BitmapFactory.decodeByteArray(data , 0, data.length);
    return bitmap;
}