save image from drawable to sd card

try{ 
 
Bitmap largeIcon = BitmapFactory.decodeResource(getResources(), R.drawable.bubble_green);
 
            //replace "R.drawable.bubble_green" with the image resource you want to share from drawable  
 
            ByteArrayOutputStream bytes = new ByteArrayOutputStream();
            largeIcon.compress(Bitmap.CompressFormat.JPEG, 40, bytes);
 
            // you can create a new file name "test.jpg" in sdcard folder. 
            File f = new File(Environment.getExternalStorageDirectory() + File.separator + "test.jpg");
 
            f.createNewFile();
 
            // write the bytes in file 
            FileOutputStream fo = new FileOutputStream(f);
            fo.write(bytes.toByteArray());
 
            // remember close de FileOutput 
            fo.close();
        } 
        catch (IOException e) {
            // TODO Auto-generated catch block 
            e.printStackTrace();
        }