After all this time, I figured the term "thumbnail" sinply meant a smaller image about the size of your thumb nail. (yes I'm old) After a little research I see it is more akin to a "link" or preview that directs one to a larger image.
Given that, I will be conducting a test to see if I can figure this out :
-----Edit-----
Test results: Success and easy as pie.
Click on the image you see above and it brings up the larger, original size image.
I simply copied the "IMG thumb" image code from my Photobucket account in lieu of the "IMG Image" code.
You learn something new every day.
.
.