Java tutorial
//package com.java2s; import java.io.ByteArrayOutputStream; import android.graphics.Bitmap; public class Main { /** * bitmap to bytes[] */ private static byte[] bitmap2Bytes(Bitmap bitmap) { if (bitmap == null) { return null; } ByteArrayOutputStream baos = new ByteArrayOutputStream(); bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos); return baos.toByteArray(); } }