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