It is very easy to retrieve image file from parse.com.

For example the image file name profilePicture is save on User class and I am going to retrieve the image below.

ImageView profilePic = (ImageView)findViewById(R.id.image_profile);
  ParseFile imageFile = (ParseFile) currentUser.get("profilePicture");
            FlexLogger.createLog("Image file :: " + imageFile);
            imageFile.getDataInBackground(new GetDataCallback() {
                @Override
                public void done(byte[] data, ParseException e) {
                    Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);


          profilePic.setImageBitmap(bitmap);
            }
        });

I got the image by doing this. Hope it will help you.