I got a few "file corrupt" errors today when transferring from Flickr. I though it was just bad luck, but then I downloaded one, saved it with Photoshop to a new file, tried to upload, same error. Tried again, saving in different quality, same thing.
Other software (e.g. Mac preview) has no problem with it either. Even got the MediaWiki upload wizard thumbnail preview, but still the error. Example: