Does art have to be intentional or representational?
My definition of art would have to be anything that is pleasing to the viewers eye. To answer the first part of the question, no, art does not have to intentional to be considered art. Many works fo art probably don't start out the way they end up. An artist may have a vision of what they want their work to look like, but that doesn't mean it will happen that way. Paint could be spilled on a canvas or the wrong color could be used for a project and it turn out to be the best work of art anyone has ever seen.
The second part of the question is also no. A piece of art does not have to be representational. Something could be art just because it looks pretty. When I look at art, I don't look to find hidden meanings behind the elements of the work, or to see what the author is trying to say. Some things are art just because they are appealing, and that's ok.