private void setFinishResult() {
        //pass back selected image index
        final Intent intent = new Intent();
        intent.putExtra(ImageViewActivity.EXTRA_IMAGEVIEW_POS, this.imagePos);
        setResult(RESULT_OK, intent);
    }
sets properties for activity to enable smooth image transation between master/list and detail activity
main/src/main/java/cgeo/geocaching/ImageViewActivity.java