Copyright lasts for the author’s life plus 70 years, but you have to work out who is the author of the work. Of course, the author may be the writer.
The author might also be the illustrator, and the author may be both. Copyright lasts for the life of the creator plus 70 years so there might be quite different copyright duration between the two.
Take The Wind in the Willows as an example. The writer Kenneth Grahame died in 1932 and his work was therefore out of copyright by 2003. The illustrator E. H. Shepard died in 1976 at the grand old age of 97 and his illustrations will be in copyright until the end of 2046.