Java tutorial
//package com.java2s; import android.graphics.Bitmap; import java.io.ByteArrayOutputStream; public class Main { /** * Converts a given bitmap to byte array **/ public static byte[] toBytes(Bitmap bmp) { ByteArrayOutputStream stream = new ByteArrayOutputStream(); bmp.compress(Bitmap.CompressFormat.PNG, 100, stream); return stream.toByteArray(); } }