Okay kiddo, let me explain it to you in a way that makes sense to a five-year-old.
So, once upon a time, a long long time ago, there was a special art show called the Salon. It was a really big deal and all the artists wanted to show their work there. But, there was a problem. The people who organized the Salon didn't like all the art that the artists were making.
They only wanted to show art that followed certain rules and looked a certain way. This made a lot of artists really upset because they worked very hard on their art and wanted to show it to people.
So, some of these upset artists decided to create their own art show called the Salon des Refusés. This means "the salon of rejected ones" in French. It was basically a show for all the art that the Salo organizers didn't want to show.
This made a lot of people really excited because they got to see all different kinds of art that they never would have seen before. Sometimes, this even made the art that was rejected more famous than the art that was accepted in the regular Salon!
So, in the end, the Salon des Refusés showed that there are many different kinds of art and that just because some people don't like it, doesn't mean it isn't worth showing to others.