After looking at several paintings, I found it difficult to get excited about any of them. Not because I didn't like them, but the web site just doesn't give the art presence. I mainly looked at oils and acrylics, and I could not get any idea of the brushwork, the texture. I just could not connect with any of them across the intertubes.
So I love the idea, but to me it seems the challenge you face is how to present the art. Sorry I don't really have any great suggestions -- more views of each piece that allow for examining the technique? More careful lighting of the photos in a way the best complements the art? It is a big challenge and I don't have any great ideas.
But there is something about being there -- we have all seen Munch's "The Scream" or Van Gogh's "Starry Night" a zillion times on the internet, on mouse pads, in cartoon parodies -- but actually standing in front of those paintings is an experience from another world. I want to get as close to that experience as I can when I look at your artist's works.
I think you need to up the curation somehow -- maybe some comments from the artist about the piece, or some very close images of exciting details.
Very sincerely best of luck, I hope you succeed for your artists.