Can I make a children's book or picture book in Pressbooks?

You can create books with photos in Pressbooks, but it's not necessarily the best platform for image-only, heavily designed books. We find that often users designing illustrated children's books or photo books may need a higher level of control over page flow than Pressbooks offers unless you've got an in-depth understanding of HTML and CSS. 

You can always try out Pressbooks for free on private books to see if it works for you.