Java tutorial
//package com.java2s; //License from project: Apache License import android.graphics.Bitmap; import java.io.ByteArrayOutputStream; import java.io.IOException; public class Main { private static byte[] bitmap2Bytes(Bitmap bm) { try { ByteArrayOutputStream baos = new ByteArrayOutputStream(); bm.compress(Bitmap.CompressFormat.PNG, 100, baos); byte[] bytes = baos.toByteArray(); baos.close(); return bytes; } catch (IOException e) { e.printStackTrace(); } return null; } }