HTML, CSS, Javascript

I found creating the questions and making the portion of the questions responsive with the correct css and styling. For the javascript code I wanted to learn to map over the classLists and display the quesitons and answers based on the manipulation of the dom. But I stuck with a certain function that basically works. I am unsure of a different way of using javascript to query the img selectors and styling them the correct way. "active" style. I would like to know if there are any details I have left out and anything I could do differently with javascript and css. Thank you for your feedback.