Babar and Celeste's kids have plenty of questions to ask of the art appreciation kind as they are looking at the portraits too. "Does it have to make sense?" was one of my favourites.
If you've visited, or planning to visit, your local art gallery, this is really worth reading to your kids. There's a list at the back of all the famous artworks featured in the book (if, like me, your art appreciation and recognition skills are limited...).