Thanx all, I have again upgraded to v4.13 to find the actual file name, which is thumbcache_idx.db that was repeatedly too hard to destroy.
When you right click on the listed item it gives you a list of thumbcache files, _sr.db, _idx.db, _32.db, _96.db, _256.db, _1024.db The _idx.db was the one that kept coming back regardless of the number of times I ran CCleaner over and over.
Doing a little checking, it seems that .db files do relate to picture files, so I rebooted my laptop, and without running any other programs, I now get a clean CCleaner Run with no retained .db files listed on the second sweep. The possibility exists, that I had retained some picture function when I found the anomaly before, that would not go away when running CCleaner. This seems to have cleared up, not sure how or why, but as long as I close browsers, programs, ITunes, Windows media player, and all other active background items, CCleaner v4.13 is clearing all listed ingredients. Don't remember needing to close anything before when running CCleaners v4.12, v4.11, v4.10....... but I now seem to be getting correct results with v4.13. Now that I know what I am looking for, I will try to recreate the conditions if it happens again.