SamsungTab10.1 Thumbnails do not match images in gallery

[SamsungTab10.1]

My images and thumbnails do not match. I moved all the images to my laptop and deleted all tablet images. Then I put a few images back on.

Using the stock Gallery SW the images have incorrect thumbnails. I click on a thumbnail, that image enlarges, then converts to the underlying image.

Any ideas how to get rid of all the thumbnail associations?

thanks.