Photo Upload/Media Library Not Working Anymore

I’m having difficulty with the new media interface.

I can upload photos, but instead of showing up as an image, they only show up as their filename, both in the Media Library and everywhere else in the WordPress Dashboard. They don’t even show up on my site when I try to publish them or use them in a post.

It doesn’t matter how large or small the image is — it’s always the same.

The photos I uploaded prior to the WordPress 3.5.1 update still work and are still visible.