In The Scarlet Letter, what are two symbolic images of good and evil that battle over Dimmesdale's soul?

As sometimes happens, I am not sure of what you mean by your question, but I will try.

In my understand, symbolic images don't "do battle." I think you are referring to the two forces that may symbolize the fight between good and evil that battle for Dimmesdale’s soul --- Chillingworth and Hester. Chillingworth is the more obvious. He is obsessed with the desire to get revenge of Dimmesdale for the wrong he has brought on Hester. He becomes the Leech, sucking the soul out of Dimmesdale, seeking not his death, but the prolongation of his agony. Dimmesdale is keenly aware of this evil. In Chapter 17, the forest scene, he tells Hester, “That man’s revenge has been blacker than my sin. He has violated, in cold blood, the sanctity of a human heart.”

The force for good in Dimmesdale’s life is, of course, Hester. The forest scene makes it clear that she has never stopped loving him and that he, could he face himself and say it, he knows that he has never stopped loving her. In this scene they touch for the first time in seven years, years where Hester has waited for him, hoping that they could escape, suffering and recovering alone, but always being there for Dimmesdale. She must be one of the sustaining forces in his life, a symbol of the love that was once the best thing in his life.

So the stage is set and the battle rages … and in the end neither force can win.