This is the Church I attended as a child. Note the long green rectangles to either side of Jesus. Those are hangings covering up vertical murals. Let me try to describe them.
I have to go by memories from 50 years ago. Funny how something you looked at every day of your life cannot be recalled in full. Only its impression remains, and it's not a pleasant one.
The paintings depicted figures from the Old Testament. The Big names, like Noah, Moses, Abraham, and even Jonah. They were all old men with white beards looking piously out on the congregation. As a kid, I was unable to identify them all, but they all looked mean.
I don't recall any discussion in school about these paintings, and I have been unable to find any images of them online. I don't know when they began covering them up, but every image I find has them concealed.
I wasn't necessarily frightened by them, but they filled me with an uncomfortable unease. The one of Jonah particularly disturbed me, as I recall it depicted him either being swallowed or emerging from the whale.
I'm guessing that I wasn't alone in my discomfort. Other kids probably were disturbed as well. This may have led to them finally being covered up. I don't know for certain.