Encode and decode bitmap object in base64 string in Android

Hope this will help you

 Bitmap bitmap = BitmapFactory.decodeStream(this.getContentResolver().openInputStream(uri));

(if you are referencing URI to construct bitmap) OR

Resources resources = this.getResources();
Bitmap bitmap= BitmapFactory.decodeResource(resources , R.drawable.logo);

(if you are referencing drawable to construct bitmap)

Then Encode it

 ByteArrayOutputStream stream = new ByteArrayOutputStream();  
 bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
 byte[] image = stream.toByteArray();
 String encodedImage = Base64.encode(image, Base64.DEFAULT);

For Decoding Logic will be exactly reverse of encoding

byte[] decodedString = Base64.decode(encodedImage, Base64.DEFAULT);
Bitmap decodedByte = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length); 

public static String encodeToBase64(Bitmap image, Bitmap.CompressFormat compressFormat, int quality)
{
    ByteArrayOutputStream byteArrayOS = new ByteArrayOutputStream();
    image.compress(compressFormat, quality, byteArrayOS);
    return Base64.encodeToString(byteArrayOS.toByteArray(), Base64.DEFAULT);
}

public static Bitmap decodeBase64(String input)
{
    byte[] decodedBytes = Base64.decode(input, 0);
    return BitmapFactory.decodeByteArray(decodedBytes, 0, decodedBytes.length);
}

Example usage:

String myBase64Image = encodeToBase64(myBitmap, Bitmap.CompressFormat.JPEG, 100);
Bitmap myBitmapAgain = decodeBase64(myBase64Image);

To encode the bimap to image:

 ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.PNG, 80, byteArrayOutputStream);
   byte[] imageBytes = byteArrayOutputStream.toByteArray();
   String encodedImage = Base64.encodeToString(imageBytes, Base64.DEFAULT);
    Log.d("bytearray", String.valueOf(byteArrayOutputStream.toByteArray()));
    Log.d("encodedimage",encodedImage);