Google indexing both pages and files on those pages

I’ve just noticed an SEO problem with my site and I was wondering if someone can help me solve it.

I did a google search for “taka-onna” to see where my page came up.
http://www.google.co.jp/search?&q=takaonna

As you can see, both entry 2 and 3 are my own site. But the problem is that entry #3 is my blog post, while entry #2 is just a link to the image file used in the blog post. I know that Google penalizes sites that do this sort of thing, and I also think it just reflects badly on the design of my site.

Can anyone help me figure out how to exclude these “subpages” of posts from being indexed? I don’t mind the images themselves being indexed by Google images, but I don’t want them to showing up as separate posts in web searches, taking away hits from my actual blog posts and possibly risking some kind of pagerank violation by Google. If nothing else, too, it’s just sloppy-looking.

Any ideas?