why app performance is slow down ?? when the camera image in gallery has been stored in imageview

App performance is slow down since camera image was stored in imageview.

Sometimes application is down. how to fix it??

 public void onClick(View v) {
        if(v.getId() == camerabutton.getId()){
            addImageView();
        }
    }

    private void addImageView(){
        Intent intent = new Intent(Intent.ACTION_PICK);
        intent.setType(MediaStore.Images.Media.CONTENT_TYPE);
        intent.setData(MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
        startActivityForResult(intent, REQ_CODE_SELECT_IMAGE);
    }

    @Override
    protected void onActivityResult(int requestCode , int resultCode , Intent data) {
        if(requestCode == 100){
            if(resultCode == Activity.RESULT_OK){
                ImageView imageView = new ImageView(this);
                ViewGroup.LayoutParams params = new ViewGroup.LayoutParams(postArea.getWidth(), ViewGroup.LayoutParams.WRAP_CONTENT);
                imageView.setLayoutParams(params);
                //params.width = postArea.getWidth();


                imageView.setLayoutParams(params);
                Uri imgUri = data.getData();
                imageView.setImageURI(imgUri);
                postArea.addView(imageView);
            }
        }
    }
}

postArea is LinenerLayout~ This code is add imageView to Layout