|Me too. These images have been destroyed and are unreadable. I have two memory cards with this issue.|
Usually, a low battery will cause this in camera's. Especially if it shuts itself down when a picture is taken. That spot on the memory stick is now unusable. Do not delete that image or other images using that spot will also be unreadable. Formatting will not recover those bad spots and make them usable. Formatting will hide them from you.
Create a folder on the memory stick and move these bad spots to that folder to keep them out of your way; if you are able.
In short, Get a new memory stick / card and camera battery for reliability.