Java tutorial
//package com.java2s; import java.io.ByteArrayOutputStream; import android.graphics.Bitmap; import android.graphics.drawable.BitmapDrawable; import android.graphics.drawable.Drawable; public class Main { public static byte[] drawableToBytes(Drawable drawable) { BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable; Bitmap bitmap = bitmapDrawable.getBitmap(); byte[] bytes = bitmapToBytes(bitmap); ; return bytes; } public static byte[] bitmapToBytes(Bitmap bm) { byte[] bytes = null; if (bm != null) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); bm.compress(Bitmap.CompressFormat.PNG, 100, baos); bytes = baos.toByteArray(); } return bytes; } }