There are multiple embedded previews in a jpeg or raw image, so seeing that it's okay in one place via a browser isn't a guarantee of where something went wrong. If you still hae the image on the original card, I'd copy it again (just that file) and see if the problem is still present. If it is, it's probably a corrupted flash card. Are you good about formatting your cards frequently when you're ready to shoot with them again or are you formatting them via your computer? The latter Is a bad idea.
If the card is corrupted and you're following good practices, I'd be inclined to stop using that card.