Images cannot be seen

Suddenly, any images in the “Uploads” subfolders cannot be seen. I have verified that the files are actually there, but even if I enter the direct URL for an image, it doesn’t show in the browser – says “Page cannot be found”. As well, the image thumbnails do not show in the Media Library. Also, when I upload a new image via the Media Library, the upload is successful, meaning that I can see the image file on the site with CuteFTP, but the image thumbnail is broken in the Media Library, and a direct access to the image’s URL gets “Page not found”. My theme’s author has taken a look and can’t figure it out. We’ve re-installed his theme, activated Twenty Twelve, deactivated all plugins, nothing works. I do have some backups of my database, but I’ve never done a restore of the DB before, so I’ll have to investigate that process.

If I move the images back out to the wp-content folder, then they can be seen, and some of the images on the site have been “fixed” using that method, but some images, such as the thumbnails on the “Our Work” page can only be inserted via the media library, not by typing in a specific URL.

Here’s the site