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