Can't see my photos!

Hello,
I have this kind of weird problem.
I transfered a bunch of pictures from my mac to my windows as i wanted to reinstall my mac. However half of the pictures i get looks like this:

http://gratisupload.dk/vis_billede/677543/

as you can see, it has bytes and everything. It just won't open.
When i try to open it, it says:

Windows photoviewer can't open this photo, either cause the format (.jpg) isn't supported or because you don't have the latest version of Windows photoviewer..

I can however open all other pictures. :S - Please help.