sqlite, blob

//******************
// uri image -> byte[]

//******************

InputStream is = (InputStream) new URL(url).getContent();

Bitmap bmp = BitmapFactory.decodeStream(is);

ByteArrayOutputStream stream = new ByteArrayOutputStream();

bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);

byte[] byteArray = stream.toByteArray();

//******************
// Bitmap -> byte array
//******************

Bitmap bmp = intent.getExtras().get("data");

ByteArrayOutputStream stream = new ByteArrayOutputStream();

bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);

byte[] byteArray = stream.toByteArray();

//******************
// Select
//******************

Cursor cs = ...
...

byte[] image = cs.getBlob(cs.getColumnIndex("blob_attr"));

Bitmap bitmap = BitmapFactory.decodeByteArray(image, 0, image.length);

-bitmap -> byte array
http://stackoverflow.com/questions/4989182/converting-java-bitmap-to-byte-array