A picture book consists of mainly of illustrations and is geared toward children who have not yet learned to read.
How to find picture books in the PLU catalog:
1) search using the term (with quotes) "picture books"
2) in the left column, select format:"book" and audience:"juvenile"
The chidren's book section is on the second floor of the library. Books are organized by Library of Congress subjects. Use the catalog to easily find books.