Libraries sometimes have exhibitions or displays related to children's stories which may include images and quotes. Also, some schools or educational institutions might create their own collections for teaching purposes, which could be a source to look into.
You can find them in children's storybooks. Many storybooks are beautifully illustrated, and they often have inspiring quotes within the text. For example, 'The Little Prince' has many profound quotes and its illustrations are charming.
Online platforms like Pinterest are great sources. Just search for 'images and quotes about children's stories' and you'll get a plethora of results. There are also websites dedicated to children's literature that might have collections of such images and quotes.