Quizzes are a great tool for adding much needed interaction during long presentations or testing learners that they have actually understood a topic. I’ve seen quizzes and interactive voting applied in lessons.
Freepik is the leading search engine of free vector designs and is my personal favourite. All of the graphics used on this site have been sourced from free libraries and as long as you attribute them your good to go.
Everyone learns in a different way. Some people are more visual eLearners who prefer to savor and digest the text in front of them, at their own pace, in the quiet comfort of their favorite learning space.