после получения растрового изображения сделайте так
Bitmap new_bmp = Bitmap.createBitmap(bm, 0, 0, linear.getWidth(), linear.getHeight(), matrix, false);
image.draw(new Canvas(new_bmp));
String s = Environment.getExternalStorageDirectory().toString();
linear.setBackgroundColor(Color.BLACK);
OutputStream outStream = null;
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_hhmmss");
String file_name = sdf.format(new Date())+".PNG";
File file = new File(s, file_name);
try {
outStream = new FileOutputStream(file);
new_bmp.compress(Bitmap.CompressFormat.PNG, 100, outStream);
outStream.flush();
outStream.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
Toast.makeText(CaptureImage.this, e.toString(), Toast.LENGTH_LONG).show();
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(CaptureImage.this, e.toString(), Toast.LENGTH_LONG).show();
}