This is the weirdest thing I have ever seen. Previously only about half of the thumbnail images were showing up. The thing is all my camera pics already have .jpg extensions. Most of my background images had .png extension and none of those thumbnails would show up. The pics would show fine when selected, just no previews. So I decided to try your advice and I renamed just one of those background images with the .png extension to .jpg. Just to see what would happen. Launched the gallery and low and behold every last one of my pics now has a thumbnail. I have no clue as to how or even why that worked. Maybe renaming a file forces the program to regenerate all thumbnails. Who knows but their showing and I'm happy again. Thanks.