Media files not appearing in media library or attachment page

I have a production site that I migrated to from my dev site several days ago. Going forward I’d like to make small changes on the production site rather than remigrating the site from dev every time, but I’ve discovered a bug of some kind relating to my media files. Here’s the skinny:

• Images appear on the site where they’ve been inserted into widgets, posts, pages, etc. No problems here.
• When I look at the media library, I can see all of the images listed but they all render as the default WordPress image icon, rather than rendering the pictures themselves.
• Clicking on an image in the media library opens the edit modal which allows me to change the meta info but again it renders the WordPress image placeholder icon and does not provide any of the usual tools for editing the image.
• Visiting the attachment page for an image renders a text link for the image rather than the image itself. Clicking the link takes you to the media itself (image rendered on a blank page) so the image is definitely there, but WordPress can’t seem to reference it within the backend.
• When editing a post or page with an image, the image does render in the WISIWYG editor but if I try to edit the image the edit modal that pops up is completely blank

None of these problems exist on the dev site. I did not check the media library when I first uploaded to dev, so I don’t know if this problem’s been there since the migration or if it was introduced more recently. Could it be an htaccess problem? Any tips greatly appreciated!