android bitmap

Bitmap.Config conf = Bitmap.Config.ARGB_8888;
WeakReference<Bitmap> bm = new WeakReference<Bitmap>(Bitmap.createBitmap(3000 + 3000, 2000, conf));

Canvas canvas = new Canvas(bm.get());
canvas.drawBitmap(firstBitmap, 0, 0, null);
canvas.drawBitmap(bm, firstBitmap.getWidth(), 0, null);

imageView.setImageBitmap(bm);

---------------orintation memory leak

private ImageView miniPicture;
private String imagePath;
private WeakReference<Bitmap> imageBitmap;

....

BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 8;
imageBitmap = new WeakReference<Bitmap>(BitmapFactory.decodeFile(imagePath, options));                
miniPicture.setImageBitmap(imageBitmap.get());

--------------

In your onDestroy method you could try something like this:
ImageView imageView = (ImageView)findViewById(R.id.my_image);
Drawable drawable = imageView.getDrawable();
if (drawable instanceof BitmapDrawable) {
    BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
    Bitmap bitmap = bitmapDrawable.getBitmap();
    bitmap.recycle();
}

public void setImageBitmap(Bitmap bm) {
    setImageDrawable(new BitmapDrawable(mContext.getResources(), bm));
}