get high quality picture from base64 string - php

Question

I'm returning image as base64 string in server side. In client side app takes this base64 string and convert it to byte[] and then to Bitmap and at the last step sets this bitmap to ImageView. My problem is returned image quality. It looks poor; I can see the pixels of this image...
Upload part
Client side (upload):
BitmapFactory.Options options = null;
options = new BitmapFactory.Options();
options.inSampleSize = 3;
bitmap = BitmapFactory.decodeFile(imgPath, options);
ByteArrayOutputStream stream = new ByteArrayOutputStream();
// Must compress the Image to reduce image size to make upload easy
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
byte[] byte_arr = stream.toByteArray();
// Encode Image to String
encodedString = Base64.encodeToString(byte_arr, 0);
Server side (accepts uploaded image):
$_image = $_REQUEST['image'];
$binary = base64_decode($_image);
// for inserting it to db...
$sql = "INSERT INTO users (`_profile_pic`) VALUES ('$_image')";
$connect->query($sql);
Accept part
Server side (gets base64 string from db)
$user_data = "SELECT _name, _profile_pic FROM users WHERE _id = {$_id}";
$data = $connect->query($user_data);
while ($row = $data->fetch(\PDO::FETCH_ASSOC))
$collectedResult[] = $row;
echo json_encode($collectedResult, JSON_UNESCAPED_UNICODE);
Client side (sets image to ImageView (problematic part) )
_picture = (ImageView) findViewById(R.id.profile_imageView);
byte[] decodedString = Base64.decode(profile_pic_value, Base64.DEFAULT);
Bitmap bmp = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length);
_picture.setImageBitmap(bmp);
At this moment I don't know how to restore or increase the quality.
Any helpful comment, answer appreciated.
Regards,
Mirjalal.
P.S This question maybe duplicate of another question(s), but I couldn't find duplicate one. :D
I found this but I don't know how to use.

Answer 1

It is possible that you loose color depth during decoding into RAM. Android has defaults as to which color format it decodes bitmaps. See following example which saves RAM but still maintains acceptable image quality.
public static Bitmap decodeBase64(String input) {
byte[] decodedByte = Base64.decode(input, Base64.DEFAULT);
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = false;
options.inPreferredConfig = Bitmap.Config.RGB_565;
return BitmapFactory.decodeByteArray(decodedByte, 0, decodedByte.length, options);
}
Take a closer look at the Bitmap.Config.RGB_565 parameter.