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