I feel that - depending on the person/their views/ideas/etc - the answer to this 'A Gallery of Compositions' could vary.
Here is what I would say:
I feel that art's role in modern society today is very much how it was years ago. It's a way to tell stories, to capture moments, to share ideas and fantasies. For example, an artist could paint a landscape. To some, it may be just that; a landscape. But to others, it could be a story, a beautiful land yet to be discovered, or even just a homage to a piece of land owned by a humble and happy farmer.
I don't know how long this composition need(s) to be, but honestly the response depends entirely upon the writers' personal views... so let them know what YOU think!! :) Hope this helped anyway!!