This series is called, "A Photographic Story of a Life." We purchased Albert Einstein, Thomas Jefferson and Helen Keller. They were on sale, such that if you bought two, you got one free, for a total of about $10.
These are what I call intermediate readers. The words are easy and there are plenty of pictures and vocabulary boxes.
They are about the size of a novel.
Other biographies in the series are: Abraham Lincoln, Gandhi, Benjamin Franklin, Marie Curie, Amelia Earhart, Thomas Edison, George Washington, Martin Luther King, Nelson Mandela, Mother Theresa, John F. Kennedy, Harriet Tubman and many more.
I would recommend these for ages 9 and up, however, I think any age would enjoy getting a quick overview of these famous people with these biographies.