[vixen99]

That's your preference. However "To illustrate is to make something more clear or visible. Children's books are illustrated with pictures. An example can illustrate an abstract idea. "illustrate" comes from the Latin illustrare 'to light up or enlighten.'"

Quote from https://www.vocabulary.com/dictionary/illustrate

[0_____0]

It's extremely obvious that the sense of "illustrated" meant here is "containing illustrations."

[sarchertech]

In the context of books or internet books illustrated almost exclusively means “with pictures”.