Darn, I used too big of a photo initially and it didn't generate a thumbnail. Sized it down some and re-uploaded but, still doesn't seem to want to use anything but blank thumbnail. Guess I'll start smaller next time. Aw well, ...what do you think @originalworks? lol
Figured out the problem. It was because image file name had spaces and parenthesis. Changed file name so no spaces or parenthesis and re-uploaded and problem was solved; thumbnail now appears correctly.