what has happened to this image?????????

this image is in my laptop and desktop. it appears normal in the desktop.
have found several others taken at a different date with same problem.

i have transferred files from my laptop to an external drive. is this particular file corrupted and should i be concerned about the files in my external drive.

also, when going though canon zoombrowser, i have come across some RAW thumbnails that are pixelated and when enlarged are ffine.

thanks.
sorry about the size.