The graffiti: Street art or crime?

Many people thinks graffiti is vandalism, other people thinks that the graffiti is a art. What we think about that? Well, we think the graffiti is a art. But first, you have to know what is art.
There are several ways you could go about art, but we think art is the way where you can express your feelings.
So graffiti is art?

 This two pieces are created by the famous Banksy. Banksy show his feelings about the society.

                                                                     

Then you can see the graffiti is art because many artist express their feeling with a spray instead of with a pencil or with a brush.