comment spam on images

I’ve had an increasing problem with comment spam on images for my WordPress blog. I use the theme coraline. I figured out an easy fix. In the theme folder, find the file image.php
Then find the single line of code near the end of the file:
<?php comments_template(); ?>
and delete it.
Upload the new version of the file to the coraline theme folder.
This prevents any and all comments on all images on the blog.
It should work for theme twentyeleven and any similar themes with an image.php file. (Make sure you save a copy of the unaltered file in case it doesn’t work for you.)

Comments and contrary opinions from persons more knowledgeable than me are welcome.