I used to have the same problem in Vista. There's a fix for it but it kept reoccurring after a while. Some database corruption I think. I got tired of it and found a better free app for viewing images.
I suggest downloading, installing & using a better free image viewer called
Faststone Image Viewer and making that your default imaging viewing app, so when you click on pictures they will open in Faststone. It's
a lot better and faster than Windows Photo Viewer.
Faststone may not be the best free
editing app out there (although it's not bad), but for image
viewing I don't think there is anything better.