how do illustrators get paid? Do they get book proceeds?

Answer 1

It depends on the contract. I have self-published, so I get all the proceeds (which turns to profit AFTER I've paid myself back for the printing and other supplies). If you work for a company on staff, you are considered 'work for hire' and get your salary, unless something else is negotiated. If you illustrate as a contractor (freelance) for a publishing company, usually you can get a flat project fee, depending on the scope, detail and distribution, etc. of the book and then royalties, if you negotiate that.

Answer 2

Generally illustrators don't receive royalties, unless the illustrator has acheived some professional fame and can dictate terms (like Michael Whelan). Most illustrators are paid by the job, if they work in childrens' books and other fiction, or they are on salary, if they work as medical or textbook illustrators. However, if the illustrator also writes the book (as is often the case where childrens' books are concerned) then the artist draws royalties as both an artist and an author.