db.attachment.get file- 'could not be opened because it is empty'

[Morgan]

db.attachment.get(id, file, function(err, body) {
        if (!err) {
          fs.writeFile(req.file.name, body);
        }
    });

Upon opening the newly-written file, I see an error message that says, "[filename] could not be opened because it is empty."

If I make an http.get request via Postman, I can see the image fine. If I look at the attachment in Cloudant, I can see the image fine.