If you add to RelativeLayout, don't forget to set imageView's position. For instance:
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(200, 200);
lp.addRule(RelativeLayout.CENTER_IN_PARENT); // A position in layout.
ImageView imageView = new ImageView(this); // initialize ImageView
imageView.setLayoutParams(lp);
// imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
imageView.setImageResource(R.drawable.photo);
RelativeLayout layout = (RelativeLayout) findViewById(R.id.layout);
layout.addView(imageView);