When orientation changes activity is destroyed and created again. If you're creating your layout using xml all widgets having @id set, should be automatically recreated with it's content. Otherwise you have to do that manually - take a look at Activity's methods onRestoreInstanceState() onSaveInstanceState()
just override them and write your own save/restore code. Some of untested code, hope, that it will give you an idea:
@Override
onSaveInstanceState(Bundle b){
b.putParcelable("image", image.getBitmap());
}
@Override
onRestoreInstanceState(Bundle b){
//you need to handle NullPionterException here.
image.setBitmap((Bitmap)b.getParcelable("image"));
}