You can identify some of your unknowns yourself. Using Paint Shop Pro, open the tubed image, then use the Eraser set at 100% opacity, 100% density, 100% hardness, size about 80 (You want to cover a large area). Then hold down the right mouse button and move your cursor around the background of the tube and the background magically appears. Look for the artists signature and magnify it a little if necessary to read it.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi