Pictures of famous cartoon characters often have copyright on them. So, its better to use those pictures which do not have copyright.
Use whatever you want to if you don't intend to take money from hub pages. You are NOT going to get in any trouble.
Only if you get permission from the copy right. If you use famous pictures from any where you need permission to do so. You can and probably will get in a lot of legal trouble, so I would NOT do it.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.