how to save a bitmap image

Question

i want save a bitmap image by a specific name(id of the emp) and save it to a file location..

but i cant any way to solve it,...

please help me out

 here is code snippt of generated bimap image..

 

String code = frst_name.Text + ";" + f_name.Text + ";" + id.Text + ";" + thana.Text;

QRCodeEncoder encoder = new QRCodeEncoder();

// encoder.QRCodeScale = 10;

Bitmap img = encoder.Encode(code);